Ukrainian Leaders Express Confidence One Week After Russian InvasionUkraine marked one week since Russia invaded the country Thursday, as Russian forces shelled major cities and the number of refugees who have fled Ukraine exceeded 1 million people. Despite Russian assaults on Kharkiv, Chernihiv and Mariupol, Britain’s Defense Ministry said Thursday they all remained in Ukrainian hands. Unclear was the status of Kherson, with Russian troops present in the city amid disputed claims of who was in control. “We are a people who in a week have destroyed the plans of the enemy,” Ukrainian President Volodymyr Zelenskyy said in a video address early Thursday. “They will have no peace here. They will have no food. They will have here not one quiet moment.” Ukraine’s Defense Minister Oleksii Reznikov cited expectations ahead of the invasion that Russia would quickly overtake Ukraine, writing on Facebook, “No one, neither in Russia nor in the West, believed that we would last a week.” He added that while there are challenges ahead, Ukraine has “every reason to be confident.” Thursday also brought the expectation of a second round of peace talks between the two sides, though there has been little sign of a potential breakthrough. An initial meeting Monday yielded only plans for further talks. U.S. Secretary of State Antony Blinken said the United States remains open to finding a diplomatic solution to the situation, but that Russia must first de-escalate. “It’s much more difficult for diplomacy to succeed when guns are firing and tanks are rolling,” he told reporters Wednesday. Blinken is traveling to Europe on Thursday for a series of meetings with NATO and other allies about their response to the Russian invasion. NATO foreign ministers are holding an extraordinary meeting Friday in Brussels, and on Saturday Blinken travels on to Poland to discuss further security and humanitarian assistance to help refugees who have fled Ukraine. Poland has taken in half of the more than 1 million refugees who have fled Ukraine in the past week, according to the U.N. High Commissioner for Refugees. The U.N. body has said it expects 4 million people could leave Ukraine due to the conflict. Ukraine’s emergency agency said Wednesday Russia’s attacks have killed more than 2,000 people across the country. Russia’s Defense Ministry put out its first casualties report, saying 498 of its troops were killed in Ukraine, while more than 1,500 others were wounded. A senior U.S. defense official told reporters Wednesday Russian forces trying to take the Ukrainian capital, Kyiv, were “stalled outside the city center." The forces, including a massive Russian convoy, have made "no appreciable movement," the official said, adding Russian advances on other key cities, such as Chernihiv and Kharkiv had also stalled. Meanwhile, shipments of defensive aid for Ukraine continued to arrive, according to U.S. officials. The Pentagon on Wednesday also expressed concerns that Russian forces are getting more aggressive in their targeting, putting civilians and civilian infrastructure in greater danger. The senior defense official said the U.S. believes that since the invasion began last Thursday, Russia has launched more than 450 missiles, but that Ukraine’s air and missile defense systems remain viable. The official said the lack of Russian progress around Kyiv, despite its superior firepower, could be attributed to factors including shortages of fuel and food, and a spirited defense by Ukrainian forces. "It has slowed because of resistance from the Ukrainians that has been effective and quite creative," the official said. "They have marshaled their assets quite well. … The will to fight is very strong, in terms of their armed forces but also in terms of their civilian population." "We also believe they [Russia] have had morale problems that has led to less than effective operational success," the official added, cautioning that U.S. intelligence expects Russian forces will adapt in order to continue with the massive assault. The Pentagon also announced that it is postponing a nuclear missile test launch scheduled for this week. The decision comes days after Russian President Vladimir Putin's decision to put his nuclear forces on higher alert. Pentagon press secretary John Kirby said the decision to delay the test of a Minuteman III intercontinental ballistic missile was made by Defense Secretary Lloyd Austin. Kirby added that the United States would like to see Moscow reciprocate by “taking the temperature down” in the crisis over Ukraine. Another factor that may be helping the Ukrainians is continued support from NATO and the United States. Blinken said Wednesday the United States is imposing sweeping sanctions on Russia’s defense sector. "In total, 22 Russian defense-related entities will be designated, including companies that make combat aircraft, infantry fighting vehicles, missiles, unmanned aerial vehicles, electronic warfare systems – the very systems now being used to assault the Ukrainian people, abuse human rights, violate international humanitarian law,” Blinken said during a news conference. Blinken said the United States would also “choke off Belarus’ ability to import key technologies” by imposing export controls on Belarus “to hold the Lukashenka regime accountable for being a co-belligerent in President [Vladimir] Putin’s war of choice.” VOA State Department Bureau Chief Nike Ching, national security correspondent Jeff Seldin, Pentagon correspondent Carla Babb, correspondent Jamie Dettmer, Islamabad Bureau Chief Heather Murdock and White House correspondent Anita Powell contributed to this report. Some information for this report came from The Associated Press, Agence France-Presse and Reuters.