In Kiev, the provisional government also said that it would quit the Commonwealth of Independence States, the group of former Soviet republics, and that it was considering imposing visa requirements on Russian citizens — a step that would potentially create huge inconveniences for Ukrainians as well, in the likely event that Russia reciprocated. 
 
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 Russia did not flinch. Outside Moscow, President Vladimir V. Putin opened a meeting of senior government ministers by demanding updates on the transportation and infrastructure in Crimea. Mr. Putin ordered that the government move swiftly to begin construction of a bridge that would provide an overland link for cars and trains directly between Crimea and Russia. At present, no such link exists. 
 
 The takeover of the base proceeded as anger intensified in the West over Russia’s move to annex Crimea, with calls for Russia’s expulsion from important international bodies like the G-8 grouping of leading economic powers. At the same time, Vice President Joseph R. Biden Jr. continued his effort to reassure American allies in the Baltic region, once part of the Soviet Union, that the United States would protect them from any aggression by Russia. 
 
 The United Nations said Wednesday that Ban Ki-moon, the secretary general, would travel to Moscow and Kiev on Thursday and Friday for meetings with leaders, including Mr. Putin, whose moves to reclaim Crimea have set off the biggest crisis in East-West relations since the Soviet Union’s demise two decades ago. 
 
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 Mr. Ban has expressed disappointment over the Kremlin-backed weekend referendum in Crimea that created the basis for Russia’s annexation, but he has said nothing about whether he considers the Russian step to be illegal. The United States and other Western members of the Security Council proposed a resolution on Saturday declaring the referendum illegal, but Russia, acting alone, vetoed that measure. 
 
 At the Ukrainian naval headquarters here, soldiers with machine guns, wearing green camouflage but still no identifying insignia, were deployed in and around the base. A large military truck just outside the base bore the black-and-white license plates of the Russian forces. 
 
 Although the gates were forced open during the initial storming of the base, there were no reports of shooting or injuries. And while there was no indication that the Ukrainian government was prepared to issue a formal surrender in Crimea, capitulation by military units surrounded throughout the peninsula seemed increasingly inevitable. 
 
 When asked why they did not return fire, one Ukrainian soldier leaving the base here said, “We had no order and no weapons.” Another said, “We met them empty-handed.” 
 
 On Tuesday evening, after reports that a shooting at another military installation, not far from the Crimean capital of Simferopol, had left at least one Ukrainian soldier dead, the Ukrainian Defense Ministry in Kiev issued a statement saying its troops had been authorized to use force to defend themselves. 
 
 At the base here in Sevastopol, however, the troops seemed to feel less of a threat of deadly harm than the resolute sense of facing eviction at gunpoint. 
 
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 The local militiamen have been guarding the perimeter of the base along with professional soldiers who have no identifying badges but whose equipment and organization leave little doubt they are Russian military personnel. The militiamen entered the base around 8 a.m. and an hour or so later hoisted a Russian flag on the main flagpole. 
 
 Andrew Yankov, a member of a local self-defense group, described the takeover as “a big victory.” 
 
 “We stood here for weeks, and now we’re finally successful,” Mr. Yankov said. “It’s also freedom for the guys inside. We took responsibility. They’re happy because they’re tired. They want to go home.” 
 
 At a far side of the base, local militia units appeared to be looting some equipment, removing a refrigerator through one gate, and throwing bags over the walls, which were then loaded onto a truck. 
 
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 The base, like other military installations across Crimea, had been surrounded since shortly after Russian forces occupied the region at the beginning of March. Several Ukrainian officers and soldiers said that they felt abandoned by the government in Kiev, which has been virtually powerless to help them, but also had given no hint of yielding until the evacuation announcement on Wednesday evening. 
 
 Governments continued to scramble for a response to the Kremlin’s audacious actions. In an interview with a San Diego television station, President Obama said the United States would continue to apply diplomatic pressure to Russia, but ruled out the use of American military forces, Reuters reported. 
 
 “There is a better path,” he said, “but I think even the Ukrainians would acknowledge that for us to engage Russia militarily would not be appropriate and would not be good for Ukraine either.” 
 
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 Speaking in Britain’s Parliament on Wednesday, Prime Minister David Cameron said the world’s leading industrialized countries should consider ejecting Russia from the G-8. The United States, Britain and their allies in the older G-7 body will meet in The Hague next week to debate further measures. 
 
 Before the crisis in Crimea, Mr. Putin was scheduled to host a gathering of the G-8 countries in June in Sochi, where the Winter Olympics were held, but Western countries have suspended their participation. “If we turn away from this crisis and don’t act,” Mr. Cameron said, “we will pay a very high price in the longer term.” 
 
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 On Thursday, leaders of the 28-nation European Union are scheduled to discuss a response over Crimea. 
 
 Germany’s government has expressed caution, reflecting its deep intertwined economic relations with Russia. Although Chancellor Angela Merkel took a tough tone with Moscow in public last week, business executives are reluctant to jeopardize trade ties, and diplomats and officials steeped in decades of conciliation with Russia are hesitant to sever avenues for negotiation. High-level talks scheduled for April have not been canceled. 
 
 Nonetheless, the German government spokesman, Steffen Seibert, speaking Wednesday after Ms. Merkel’s weekly cabinet meeting, said that Russia was “pursuing a path of international isolation, and it is a path containing great dangers for the coexistence of states in Europe.” 
 
 He also gave the first official response to Mr. Putin’s appeal on Tuesday to the German people to support what he depicted as Russian reunification, just as Russia supported German reunification in 1990. 
 
 German reunification brought together two German states, Mr. Seibert said, while “Russia’s intervention, by contrast, is leading to a division of Ukraine.” ||||| Media playback is unsupported on your device Media caption Watch key footage as pro-Russians take over Sevastopol navy base 
 
 Ukraine is drawing up plans to withdraw its soldiers and their families from Crimea, Kiev's security chief says. 
 
 Andriy Parubiy said they wanted to move them "quickly and efficiently" to mainland Ukraine. 
 
 Earlier, pro-Russian forces seized two naval bases - including Ukraine navy's HQ - in Crimea. Kiev says its navy chief has been detained. 
 
 It comes a day after Crimean leaders signed a treaty with Moscow absorbing the peninsula into Russia. 
 
 A referendum in Crimea on Sunday, approving its split from Ukraine, came nearly a month after Kiev's pro-Russian President Viktor Yanukovych was replaced by Western-leaning interim authorities. 
 
 Analysis In modern times, Moscow has staged three major invasions: Hungary in November 1956 and Czechoslovakia in August 1968, when the Communist governments there began showing dangerously Western tendencies; and Afghanistan in December 1979, when the pro-Communist regime was on the point of collapse. These were huge and brutal operations, involving large numbers of tanks, and sometimes great bloodshed. The takeover of Crimea has been completely different. This was an infiltration, not an invasion. And unlike in Hungary, Czechoslovakia and Afghanistan it was welcomed by a large proportion of the local population. Smoothest invasion of modern times 
 
 Nato Secretary General Anders Fogh Rasmussen has called the crisis in Crimea "the gravest threat to European security and stability since the end of the Cold War". 
 
 There were charged exchanges in a session of the UN Security Council, during which US envoy Samantha Power said her Russian counterpart Vitaly Churkin "showed more imagination than Tolstoy or Chekhov". 
 
 "Russia it seems has re-written its borders but it cannot rewrite the facts," said Ms Power, who was then accused by Mr Churkin of dropping "to the level of the tabloid press". 
 
 'Demilitarised zone' 
 
 Mr Parubiy, in a news conference, set out more details on Kiev's position in light of the events in Crimea. 
 
 He said arrangements were now being set up to introduce visas for Russian nationals travelling to Ukraine. 
 
 And he said Kiev was seeking UN support to "proclaim Crimea a demilitarised zone", which would involve the withdrawal of Russian troops and the "relocation of Ukrainian troops to continental Ukraine as well as facilitate evacuation of all the civilian population who are unwilling to remain on the occupied territory". 
 
 Ukraine is also leaving the Moscow-led Commonwealth of Independent States (CIS) alliance, and is preparing for military exercises with the US and the UK, Mr Parubiy added. 
 
 With reference to plans to withdraw troops and their families, Ukraine's interim Foreign Minister Andriy Deshchytsya told the BBC that they would not be forced to leave if they did not want to. 
 
 But he said: "The situation is unpredictable and uncontrolled sometimes, so that's why there is a danger also for the civilians". 
 
 Meanwhile, a deadline of 21:00 local time (19:00 GMT) set by Ukraine's interim President Olexander Turchynov for the release of navy chief Serhiy Hayduk has passed. 
 
 Shortly afterwards, Russian Defence Minister Sergei Shoigu called on the Crimean authorities to release him. 
 
 A defence ministry statement said Commander Hayduk had been obliged to carry out orders in accordance with Ukrainian military regulations. 
 
 Mr Turchynov earlier said that unless Serhiy Hayduk and "all the other hostages - both military and civilian ones - were released, the authorities would carry out an adequate response... of a technical and technological nature". 
 
 It is not clear exactly what he means, but it could involve the electricity or water that Ukraine supplies to Crimea, the BBC's David Stern in Kiev suggests. 
 
 Image copyright AP Image caption Pro-Russian crowds broke into the Ukrainian navy headquarters in Sevastopol 
 
 Image copyright AFP Image caption They removed Ukrainian symbols including this gate 
 
 Image copyright AP Image caption Ukrainian flags have been removed and replaced with Russian ones 
 
 Image copyright AFP Image caption Many Ukrainian officers left the base, although some said they would not surrender 
 
 Kiev said Mr Hayduk was detained soon after Ukraine's naval headquarters was stormed by some 200 pro-Russian activists, some armed, in Sevastopol - the port city which is also home to Russia's Black Sea fleet. 
 
 They were filmed going through offices, removing Ukrainian insignia and replacing Ukraine's flag with the Russian tricolour. 
 
 There were cheers from the crowd when Russia's Black Sea Fleet commander Aleksandr Vitko arrived and entered the building. 
 
 A handful of Ukrainian servicemen have refused to surrender. One told the BBC's Mark Lowen that they had been told to stay overnight to protect the equipment but fully expected to be told by Kiev in the morning to withdraw. 
 
 Media playback is unsupported on your device Media caption Footage shows the head of Ukraine state TV being beaten until he signs his own resignation letter 
 
 Ukraine's navy base in Novo-Ozyorne in west Crimea was also infiltrated after a tractor was used to ram the front gates. Some 50 Ukrainian servicemen were seen filing out of the base. 
 
 Ukrainian Defence Minister Ihor Tenyukh and First Deputy Prime Minister Vitaly Yarema reportedly tried to enter Crimea to defuse tensions but were prevented from doing so. 
 
 'Clear warning' 
 
 Earlier on Wednesday, Russia's constitutional court approved the treaty absorbing Crimea into the Russian Federation. The treaty now only needs ratifying by parliament which correspondents say it is certain to do. 
 
 Crisis timeline 21 Nov 2013: President Viktor Yanukovych abandons an EU deal 
 
 President Viktor Yanukovych abandons an EU deal Dec: Pro-EU protesters occupy Kiev city hall and Independence Square 
 
 Pro-EU protesters occupy Kiev city hall and Independence Square 20-21 Feb 2014: At least 88 people killed in Kiev clashes 
 
 At least 88 people killed in Kiev clashes 22 Feb: Mr Yanukovych flees; parliament removes him and calls election 
 
 Mr Yanukovych flees; parliament removes him and calls election 27-28 Feb: Pro-Russian gunmen seize key buildings in Crimea. Parliament, under siege, appoints pro-Moscow Sergei Aksyonov a PM 
 
 Pro-Russian gunmen seize key buildings in Crimea. Parliament, under siege, appoints pro-Moscow Sergei Aksyonov a PM 6 Mar: Crimea's parliament votes to join Russia 
 
 Crimea's parliament votes to join Russia 16 Mar: Crimea voters choose to secede in disputed referendum 
 
 Crimea voters choose to secede in disputed referendum 17 Mar: Crimean parliament declares independence and formally applies to join Russia 
 
 Crimean parliament declares independence and formally applies to join Russia 18 Mar: Russian and Crimean leaders sign deal in Moscow to join the region to Russia Ukraine crisis timeline 
 
 In an emotionally charged speech on Tuesday, President Vladimir Putin said Crimea had "always been and remains an inseparable part of Russia". 
 
 Meanwhile, shocking footage has emerged of MPs from Ukraine's far-right Svoboda party roughing up Oleksandr Panteleymonov, the acting chief executive of the state broadcaster, over his decision to broadcast the treaty ceremony in the Kremlin. 
 
 The crisis in Crimea is expected to dominate a meeting of European Union leaders who meet in Brussels on Thursday. 
 
 UK Prime Minister David Cameron said the EU must send "a very clear warning" to Russia, raising the possibility of further sanctions against Moscow. He also said the G8 group should discuss whether to expel Russia "if further steps are taken". 
 
 Moscow said any expansion of sanctions was "unacceptable and will not remain without consequences". 
 
 UN Secretary General Ban Ki-moon is heading to the region. He will meet Mr Putin in Moscow on Thursday and Ukraine's interim leaders in Kiev on Friday. 
 
 Pro-Russian forces effectively took over Crimea - with its predominantly ethnic Russian population - after Mr Yanukovych fled Ukraine on 22 February following protests in which more than 80 people were killed. 
 
 Are you in the region? Email us haveyoursay@bbc.co.uk adding 'Crimea' in the subject heading and include your contact details. ||||| UNITED NATIONS (AP) — U.N. Secretary General Ban Ki-moon is heading to Moscow and Kiev to meet with President Vladimir Putin and other officials Thursday and Friday in efforts to resolve the crisis over the Crimean Peninsula. 
 
 U.N. United Kingdom Ambassador Mark Lyall Grant, left, and U.S. Ambassador to the U.N. Samantha Power confer during a meeting of the U.N. Security Council on the crisis in the Ukraine, Wednesday March... (Associated Press) 
 
 U.N. Russian Ambassador Vitaly Churkin speaks, during a meeting of the U.N. Security Council on the crisis in Ukraine, Wednesday March 19, 2014, at United Nations Headquarters. (AP Photo/Bebeto Matthews) (Associated Press) 
 
 U.N. Russian Ambassador Vitaly Churkin arrives early and is seated alone as he waits for the start of a U.N. Security Council meeting on the crisis in the Ukraine, Wednesday March 19, 2014, at United... (Associated Press) 
 
 U.N. Ukraine Ambassador Yuriy Sergeyev speaks during a meeting of the U.N. Security Council on the crisis in the Ukraine, Wednesday March 19, 2014, at United Nations Headquarters. (AP Photo/Bebeto Matthews) (Associated Press) 
 
 U.N. Russian Ambassador Vitaly Churkin, far left, listens as U.S. Ambassador to the U.N. Samantha Power, far right, is critical of Russian actions in the Ukraine as she speaks during a meeting of the... (Associated Press) 
 
 The United Nations also announced the deployment of a 34-member human rights monitoring mission to Ukraine, scheduled to be in place by Friday. 
 
 Assistant Secretary-General for Human Rights Ivan Simonovic briefed the Security Council on Wednesday on his recent visit to Ukraine. He expressed particular concern over the security of Tatars and other ethnic minorities in Crimea. 
 
 Simonovic highlighted the disappearance of a Tatar activist after participating in a March 3 protest. Simonovic said the activist was found dead March 16 and his body bore marks of "mistreatment." 
 
 Russian Ambassador Vitaly Churkin dismissed Simonovic's assessment as "one-sided." ||||| Ukraine is planning to withdraw its forces and their families from Crimea "quickly and efficiently" after more Ukrainian bases were taken over by local militias and Russian troops on Wednesday. 
 
 Andriy Parubiy, head of the national security and defence council, told reporters in Kiev that it planned to relocate 25,000 service personnel and families. "We are developing a plan that would enable us not only to withdraw servicemen but also members of their families in Crimea, so that they could be quickly and efficiently moved to mainland Ukraine." 
 
 His comments came before Russian forces took over a naval base in Bakhchisaray in Crimea on Wednesday night, the latest in a series of takeovers of Ukrainian bases by Russian troops and local self-defence forces using a mixture of attrition and threats, as well as the dawning realisation that Kiev has lost control over the peninsula and has no way of fighting to regain it. 
 
 On Wednesday, the day after Vladimir Putin announced that Russia would absorb Crimea and a Ukrainian soldier was shot dead by a sniper at a base in Simferopol, a pro-Russian militia took control of the Ukrainian naval headquarters in Sevastopol. 
 
 "We freed the prisoners inside this base. This is Russian territory. Moscow already accepted Crimea," said Vladimir Melnik, head of a local self-defence unit, shortly after the Russian flag was raised at the base. 
 
 According to Melnik, several branches of the local militia co-ordinated in storming of the site during the morning. "We are peaceful people, but we are military people and if we receive orders to storm we will follow them," he said, adding that the civil defence units were under the command of the city administration. 
 
 Andrey Kochebarov, a deputy leader of local Cossacks, said: "There was no fight, no resistance; the guys inside clearly understood what situation they are in. This is the naval base headquarters so if they gave up this one, they will give them all up." 
 
 In the hours that followed, the Ukrainian troops, who had been inside the besieged base for three weeks, slowly trickled out with heads bowed. Morale is low and the soldiers say they are uncertain what the future holds. 
 
 "We have no word from Kiev about what to do next," said Sergei, who has served as an officer in the Ukrainian army for 21 years and remained inside the building until the bitter end. "Of course, there was no resistance [when the building was stormed]. What are we meant to do, outnumbered and without weapons?" Sergei denied the local militia's claims that the men inside were liberated: "This is a lie. We remained there of our own free will." 
 
 Sergei, from Sevastopol, said he and the 50 colleagues who remained inside had been able to leave the building, but would not have been able to return if they did so. "I stayed because I swore an oath to the Ukrainian army." He said the Ukrainian officers were not physically threatened, but they were kept without enough food and water, and the electricity was often shut off. 
 
 Outside, his tearful wife greeted him with a hug. "It's been a very difficult time. I was very anxious about his safety," she said. "I'm delighted to have him back." 
 
 Tough decisions lie ahead for all the troops in the Crimea region who have remained loyal to Ukraine. Russian and Crimean officials have issued an ultimatum to the Ukrainian troops either to join the Russian army or take the option of a safe passage out of the peninsula. 
 
 Parubiy said the Ukrainian government would appeal to the UN to declare Crimea a de-militarised zone, which he hoped would lead to Russia and Ukraine both withdrawing its forces. 
 
 The Ukrainian navy commander, Serhiy Haiduk, was captured during the storming of the headquarters and was believed to have been taken into Russian detention. On Wednesday evening, acting Ukrainian president Oleksandr Turchynov gave the Russians and Crimean authorities three hours to free Haiduk or face "adequate responses, including of a technical and technological nature", without clarifying further. 
 
 There was no immediate time frame given for Parubiy's announcement that the troops would be relocated. 
 
 Ukrainian politician Vitali Klitschko had earlier said Ukraine should not recognise Russian rule over Crimea, but did call for safe passage to be granted so Ukrainian troops on the peninsula could withdraw to "temporary bases" elsewhere in Ukraine, to prevent further bloodshed. 
 
 The Ukrainian government wanted to dispatch two ministers to Crimea on Wednesday to "resolve the situation", but were informed by Crimean authorities that they would not be allowed to enter the territory. 
 
 The process of annexation continued apace, with Ukrainian signs being removed from government buildings. Russia's constitutional court reviewed the treaty to join Crimea to Russia and found it legal, and the parliament is expected to ratify the decision by the end of the week. 
 
 Putin announced that a rail and road bridge connecting the Crimean peninsula to Russia across the two-mile Kerch Strait would be built. 
 
 Russia had already begun distributing passports in the region, said Konstantin Romodanovsky, head of Russia's federal migration service. "Some passports were issued today, and the work will only get more intensive with each new day," he told RIA Novosti. He did not clarify what would happen with those Crimea residents who did not take up Russian citizenship. 
 
 Concerns have been voiced about the fate of Crimean Tatars, who make up 13% of the population and, on the whole, are loyal to Kiev. They mostly boycotted the hastily organised referendum that returned a 97% vote for union with Russia. Crimean officials have said some of them may have to return land to which they do not own proper legal rights. Many Tatars live on unregistered land; they were deported en masse during the Stalin era and often found their property in new hands when they returned a generation later. 
 
 The most pressing issue remains what happens with the remaining Ukrainian servicemen in bases. Crimean authorities claimed that the officer who was shot dead on Tuesday was shot by a 17-year-old radical Ukrainian nationalist, which has been dismissed as implausible by authorities in Kiev. 
 
 A spokesperson for the defence ministry was unable to clarify how many soldiers were left on bases, saying he did not know himself. But there was little fighting talk at bases around the peninsula and more of a sense of resignation that the territory has been lost. 
 
 Evgeniy Cherednichenko, an officer at the logistical command centre in Sevastopol, on Wednesday made the decision to abandon his position inside the besieged base. 
 
 "It's a very difficult and complicated situation. We don't have proper information. In the end, I just decided to pick up my personal stuff and leave," he said. "I have not deserted the Ukrainian army, I don't know what to do next." 
 
 The base is surrounded by Russian troops; through the wire fence it is possible to see the Ukrainian troops moving around. A sniper sits calmly on top of a garage watching the men below. 
 
 Speaking by telephone from inside the base, lieutenant colonel Aleksandr Lusyan said: "Kiev should have given the order to use weapons at the beginning, because then we could fight back, but they were afraid to give this command because they were afraid to spill blood. Now we are outnumbered and we cannot fight back."
– It looks like Vladimir Putin's swift annexation of Crimea will be a largely peaceful one, too. Ukraine is pulling all of its troops and their families out of the peninsula and relocating them on the mainland, reports the Guardian. The announcement by the government "effectively amounted to a surrender of Crimea, at least from a military standpoint," says the New York Times account of the move. Not that it was a huge surprise: Hours earlier, Russia-backed forces seized two more naval bases without a fight and even detained the head of Ukraine's navy in Sevastopol, reports the BBC. “We had no order and no weapons," said one Ukraine soldier in Sevastopol when asked why there was no resistance. He and others were seen gathering up personal belongings and streaming off the base. Meanwhile, UN chief Ban Ki-moon is on his way to Kiev and Moscow for meetings tomorrow and Friday with Putin and others, reports the AP. The meetings come as the international community weighs its next steps on how to penalize Russia. In a speech in Washington, NATO Secretary-General Anders Fogh Rasmussen called the situation in Crimea "the gravest threat to European security and stability since the end of the Cold War."