Islamic State militants in Iraq and Syria now have about 20,000 to 31,500 fighters on the ground, the Central Intelligence Agency said Thursday, much higher than a previous estimate of 10,000. 
 
 Among those in Syria are 15,000 foreign fighters including 2,000 Westerners, some of whom have joined IS, a US intelligence official told AFP. 
 
 The figures were revealed one day after President Barack Obama vowed to expand an offensive against IS extremists, a plan which foresees new air strikes against IS in Syria, expanded attacks in Iraq and new support for Iraqi government forces. 
 
 "CIA assesses the Islamic State of Iraq and the Levant (IS) can muster between 20,000 and 31,500 fighters across Iraq and Syria, based on a new review of all-source intelligence reports from May to August," CIA spokesman Ryan Trapani said in a statement. 
 
 "This new total reflects an increase in members because of stronger recruitment since June following battlefield successes and the declaration of a caliphate, greater battlefield activity, and additional intelligence," he said. 
 
 Senior US officials have voiced concern at the presence of foreign fighters among the Sunni extremists who hold Western passports, potentially enabling them to return from the battlefield prepared to carry out terror attacks in Europe or the United States. 
 
 IS militants have seized large swathes of territory in Iraq in recent months, displaying brutal tactics and releasing videos of the grisly executions of two American reporters. 
 
 The White House has insisted that President Barack Obama is authorized to strike IS in Iraq and Syria under a law passed by Congress after the September 11 attacks in 2001. 
 
 However Obama learned Thursday that he may have a wait on his hands before Congress signs off on his plan to train and equip Syrian rebels, a key plank in his strategy to destroy Islamic State radicals. 
 
 Also on Thursday the Pentagon announced that US combat aircraft will soon start flying out of a base in the Kurdish region of northern Iraq as part of a "more aggressive" air campaign against IS jihadists. 
 
 The use of Arbil air base reflects the broadening US offensive, though attack helicopters already have been flying out of bases in Iraq. 
 
 The announcement came on the 13th anniversary of the September 11 attacks in 2001 -- a day that fell, in a trace of bitter irony, only hours after Obama's remarks steeling Americans for a battle against Muslim fanaticism in the Middle East. 
 
 ddl-gde-bfm/pvh ||||| BEIRUT, Lebanon — President Obama’s determination to train Syrian rebels to serve as ground troops against the Islamic State in Iraq and Syria leaves the United States dependent on a diverse group riven by infighting, with no shared leadership and with hard-line Islamists as its most effective fighters. 
 
 After more than three years of civil war, there are hundreds of militias fighting President Bashar al-Assad — and one another. Among them, even the more secular forces have turned to Islamists for support and weapons over the years, and the remaining moderate rebels often fight alongside extremists like the Nusra Front, Al Qaeda’s affiliate in Syria. 
 
 “You are not going to find this neat, clean, secular rebel group that respects human rights and that is waiting and ready because they don’t exist,” said Aron Lund, a Syria analyst who edits the Syria in Crisis blog for the Carnegie Endowment for International Peace. “It is a very dirty war and you have to deal with what is on offer.” 
 
 Analysts who track the rebel movement say that the concept of the Free Syrian Army as a unified force with an effective command structure is a myth. ||||| Image copyright AFP Image caption IS militants have threatened minorities and carried out extrajudicial killings in Iraq and Syria 
 
 The CIA says the Islamic State (IS) militant group may have up to 31,000 fighters in Iraq and Syria - three times as many as previously feared. 
 
 A spokesman said the new estimate was based on a review of intelligence reports from May to August. 
 
 IS has seized vast swathes of Iraq and beheaded several hostages in recent months, leading to US airstrikes. 
 
 US Secretary of State John Kerry is visiting Turkey, seeking more support for action against IS. 
 
 US officials say retired Gen John Allen will be tasked with forming an international coalition to fight IS. 
 
 'Stronger recruitment' 
 
 On Thursday, 10 Arab countries agreed to help the US attack the group in both Iraq and Syria. 
 
 The CIA had previously believed that IS had about 10,000 fighters, spokesman Ryan Trapani said. 
 
 "This new total reflects an increase in members because of stronger recruitment since June following battlefield successes and the declaration of a caliphate, greater battlefield activity, and additional intelligence," he added. 
 
 The revision comes a day after President Obama outlined a plan to "degrade and destroy" IS and to increase military support for allied forces engaged in fighting the group. 
 
 For the first time, he authorised air strikes against the group in Syria. 
 
 Media playback is unsupported on your device Media caption John Kerry: "We believe we can take on ISIL [the previous name for IS] in the current coalition that we have" 
 
 In recent months IS has expanded from its stronghold in eastern Syria and seized control of more towns, cities, army bases and weaponry in Iraq. 
 
 The US has already carried out more than 150 air strikes against IS in Iraq. It has also sent hundreds of military advisers to assist Iraqi government and Kurdish forces, but has ruled out sending ground troops. 
 
 Other countries, including the UK, have contributed humanitarian assistance to Iraqis displaced by the group's advance. 
 
 Image copyright AP Image caption The group declared the creation of a "caliphate" in the areas under its control in June 
 
 Mr John Kerry secured the co-operation of several Arab countries during a meeting in Jeddah, Saudi Arabia on Thursday. 
 
 Nato member Turkey, however, refused to sign a communique calling for countries to join the US in the fight against IS. 
 
 Analysts say this may be because the group currently holds 49 Turkish citizens, including diplomats. 
 
 Mr Kerry downplayed the move, saying the important US ally was dealing with some "sensitive issues". 
 
 He is due to travel to Turkey on Friday to try to secure more co-operation from the government. ||||| The Syrian government and its close allies in Moscow and Tehran warned Barack Obama that an offensive against Islamic State (Isis) within Syria would violate international law yesterday, hours after the US president announced that he was authorising an open-ended campaign of air strikes against militants on both sides of the border with Iraq. 
 
 Syrian opposition groups welcomed Obama's announcement and called for heavy weapons to fight the "terror" of Isis and Bashar al-Assad. Saudi Arabia and nine other Arab states pledged to back the US plan "as appropriate". 
 
 Hadi al-Bahra, head of the western-backed Syrian National Coalition, said the group "stands ready and willing to partner with the international community not only to defeat Isis but also rid the Syrian people of the tyranny of the Assad regime". In Reyhanli, on the Turkish-Syrian border, a spokesman for the Free Syrian Army (FSA) said that moderate anti-Assad forces urgently needed anti-tank and anti-aircraft missiles. 
 
 But long-standing international divisions over Syria were starkly highlighed in the hours after the speech. Iran's foreign ministry said that "the so-called international coalition to fight the Isil [Islamic State] group ... is shrouded in serious ambiguities and there are severe misgivings about its determination to sincerely fight the root causes of terrorism." 
 
 Russia said it would not support any military action without a UN resolution authorising it. "The US president has spoken directly about the possibility of strikes by the US armed forces against Isil positions in Syria without the consent of the legitimate government," said a spokesman. "This step, in the absence of a UN security council decision, would be an act of aggression, a gross violation of international law." China said that the world should fight terror but that national sovereignty must be respected. 
 
 In Damascus, the Assad government warned against US raids. "Any action of any kind without the consent of the Syrian government would be an attack on Syria," said the national reconciliation minister, Ali Haidar. Analysts believe, however, that Assad would be likely to ignore strikes on Isis targets – and even seek to quietly cooperate with western efforts. 
 
 In a meeting with Staffan de Mistura, the new UN envoy for Syria, Assad stressed his commitment to fight "terrorism" but he made no mention of the US president's speech on Wednesday night. 
 
 "As long as air strikes only hit Isis they will be condemned as a violation of international law but won't be dealt with as aggression that requires retaliation," Jihad Makdissi, a former Syrian diplomat, told the Guardian. 
 
 iraq us attacks 1209 
 
 Obama used a long-heralded address on the eve of the 13th anniversary of the 9/11 attacks to lay out his response to the appearance of an aggressive jihadi insurgency in the heart of the Arab world. US polls show growing support for military action since Isis fighters captured large areas of northern Iraq and eastern Syria and beheaded two American citizens in the past month. 
 
 He compared the campaign to those waged against al-Qaida in Yemen and Somalia, where US drones, cruise missiles and special operations raids have battered local affiliates without, however, notably improving the stability of either country or dealing decisive blows. 
 
 Obama's new strategy won swift if vague support from America's Arab allies, with Saudi Arabia agreeing to train Syrian rebel fighters. John Kerry, the US secretary state, held talks in the port city of Jeddah with ministers from Iraq, Jordan, Lebanon, Egypt and six Gulf states. After the meeting, participants said they had agreed "as appropriate" to "many aspects" of the military campaign against Isis, to stop the flow of funds and fighters and help rebuild communities "brutalised" by the group. Support was also expressed for the new, more inclusive Baghdad government – seen as vital to persuade Iraq's disaffected Sunnis not to support Isis. MPs in Jordan, warned, however, that they would not tolerate any participation in US action. 
 
 "We welcome this new strategy," said Hoshyar Zebari, a Kurdish politician and one of Iraq's newly appointed deputy prime ministers. "There is an urgent need for action. People cannot sit on the fence. This is a mortal threat to everybody." 
 
 There was confusion over Britain's role after Philip Hammond, the foreign secretary, said the UK would not take part in air strikes. But Downing Street quickly announced that UK participation had not been ruled out. Germany said it would not participate. Both countries have sent weapons and ammuniction to the Iraqi Kurds – part of the overall anti-Isis strategy. 
 
 The Pentagon is currently working on identifying suitable targets in Syria, according to White House officials. The US will also deploy a further 475 troops to Iraq, where they are expected to help identify targets. 
 
 US officials said that Kerry would be seeking to pressure Kuwait and Qatar to stop their citizens financing al-Qaida and Isis. The Saudis, stung by accusations of support for the jihadis, have already worked to crack down on funding and announced the arrest of scores of alleged terrorist sympathisers in recent weeks. 
 
 Obama said the air strikes were a necessary counter-terrorism measure to prevent the group from becoming a future threat to the US and therefore did not require fresh congressional approval. But he is expected to receive overwhelming congressional support for separate authorisation to provide military support to rival Syrian rebels like the FSA, a vote that some Republicans fear could help boost Democratic chances in this November's midterm elections by providing political support for his tough new foreign policy.
– The CIA says the number of fighters it believes ISIS can muster in Iraq and Syria has tripled in the space of months. The new estimate of between 20,000 and 31,500 fighters on the ground is based on intelligence gathered between May and August, reports the BBC. "This new total reflects an increase in members because of stronger recruitment since June following battlefield successes and the declaration of a caliphate, greater battlefield activity, and additional intelligence," a CIA spokesman says. An intelligence official tells AFP that the estimate includes some of the estimated 15,000 foreign fighters—including 2,000 Westerners—who have joined the Syrian civil war. President Obama unveiled his anti-ISIS strategy Wednesday night—to very mixed reactions. Saudi Arabia is among the Arab allies that have joined the coalition against ISIS, but analysts warn that the effort faces multiple obstacles, the Guardian reports. There is little intelligence on potential targets for airstrikes in eastern Syria, raising the risk of civilian casualties, and the anti-ISIS rebel groups the coalition will arm and train come with their own problems. "You are not going to find this neat, clean, secular rebel group that respects human rights and that is waiting and ready, because they don't exist," a Syria analyst tells the New York Times. "It is a very dirty war and you have to deal with what is on offer."