Biden Meeting in Warsaw with Polish President, Ukrainian RefugeesWARSAW — U.S. President Joe Biden is meeting in Warsaw Saturday with Polish President Andrzej Duda and other Polish officials to discuss Russia’s invasion of Ukraine, as Russia appears to have shifted its military offensive away from Ukraine's capital of Kyiv and toward the country’s east. Poland, a NATO member, has accepted more than 2 million Ukrainian refugees. Biden, accompanied by Warsaw Mayor Rafal Trzaskowski, is expected to meet some refugees Saturday to discuss humanitarian relief efforts. Later Saturday, Biden will deliver an address at Warsaw’s Royal Castle concerning the “stakes of this moment,” according to White House National Security Adviser Jake Sullivan. Friday in Poland, Biden praised Poland’s response to the refugee crisis and he met with Polish humanitarian workers and American troops near the border with Ukraine. “You are in the midst of a fight between democracies and oligarchs,” Biden said as he met in Rzeszów with members of the U.S. Army’s 82nd Airborne Division, which is supporting thousands of other NATO troops in eastern flank countries that include Poland, Lithuania, Latvia, Estonia, Bulgaria and Romania. Biden’s first visit with U.S. service members in Poland on Friday was in a makeshift barbershop at the division’s temporary headquarters. He then stopped at a dining facility for the troops, where he sat and shared pizza with them. “You are the finest fighting force in the world and that's not hyperbole,” Biden said before sitting down to eat with the troops. Change in strategy In contrast, U.S. and Western officials said Friday that despite their superior numbers, Russian forces continued to struggle in Ukraine, prompting a change in strategy. “We think they're trying to cut off the Donbas area,” a senior U.S. defense official told reporters, speaking on the condition of anonymity in order to discuss intelligence. “We've been talking about this for weeks now,” the official said of the shift in Moscow’s military priorities. “That's where still, there remains a lot of heavy fighting, and we think they are trying to not only secure some sort of more substantial gains there as a potential negotiating tactic at the table, but also to cut off Ukrainian forces in the eastern part of the country.” Russia’s deputy chief of the general staff, Colonel General Sergei Rudskoi, all but confirmed the change in focus, saying that the first stage of Russia’s operation — focused on reducing Ukraine's fighting capacity — has "generally been accomplished.” He said Russian forces are now focusing on “the main goal, liberation of Donbas.” Western intelligence estimates, however, noted the shift in strategy might be, in part, an effort to salvage a Russian war plan that has failed to topple Ukraine’s government as quickly as hoped. “Ukrainian counter-attacks, and Russian Forces falling back on overextended supply lines, has allowed Ukraine to re-occupy towns and defensive positions up to 35 kilometers east of Kyiv,” Britain’s Defense Attache to the U.S., Air Vice-Marshal Mick Smeath, said in a statement Friday. Russia’s attempted drive toward the southwestern seaport city of Odesa is “being slowed by logistic issues and Ukrainian resistance,” Smeath said. Western officials further confirmed Ukrainian forces have made progress in the town of Makariv, west of Kyiv, and that there are indications Ukrainian troops “are pushing the Russians back” in Chernihiv, to the north. The senior U.S. defense official also said Russian forces are no longer in full control of the southern city of Kherson, the first major Ukraine city to fall to Moscow’s forces. The series of setbacks appear to have been enough to prompt Russia’s military to call for reinforcements, with indications that Russian troops are being brought in from Georgia, though their ultimate destination is unclear. But there are questions as to whether more troops will be enough to help a Russian military that has not yet been able to overcome logistics and communication issues, as well as significant failure rates with its precision guided missiles, that a senior U.S. defense official said could be as high as 60% on some days. Fighting in other parts of Ukraine is being described as “vicious,” sparking concerns about the fate of civilians. Ukrainian President Volodymyr Zelenskyy said in a video address late Friday that efforts by Ukrainian forces have dealt Russia "powerful blows." He said Ukraine’s resistance should encourage Russia to seek a negotiated solution. "Our defenders are leading the Russian leadership to a simple and logical idea: we must talk, talk meaningfully, urgently and fairly," Zelenskyy said. Humanitarian situation Biden, after visiting U.S. troops in Poland on Friday, was briefed on the humanitarian situation at the Rzeszów-Jasionka Airport and said that he was disappointed that he could not see the humanitarian crisis in Ukraine firsthand. “They won't let me, understandably, I guess, cross the border and take a look at what's going on in Ukraine," he said. Biden referred to Russian President Vladimir Putin as "a man who, quite frankly, I think is a war criminal," adding, "and I think we'll meet the legal definition of that as well." Biden has previously referred to Putin as a war criminal, sparking anger from Russia. Earlier Friday, Biden met with European Commission President Ursula von der Leyen in Brussels. After their meeting, they announced formation of a joint task force to reduce Europe’s dependence on Russian fossil fuels. Biden said Putin has used the profits from Russia’s energy sales “to drive his war machine” in Ukraine. Biden said he wanted “to make it clear that the American people would not be part of subsidizing Putin’s brutal, unjustified war against the people of Ukraine.” “We are determined to stand up against Russia's brutal war,” von der Leyen said. “This war will be a strategic failure for Putin.” The United States is providing Europe with 15 billion cubic meters of liquefied natural gas this year. Chief National Correspondent Steve Herman, National Security Correspondent Jeff Seldin and U.N. Correspondent Margaret Besheer contributed to this report. Some information for this report came from The Associated Press, Agence France-Presse and Reuters.