Biden tells U.S. troops in Poland they are fighting for democracy; 300 people feared dead in Mariupol theater bombing

This has been CNBC's live blog covering updates on the war in Ukraine. [Follow the latest updates here.]

U.S. President Joe Biden stopped in Poland on Friday to meet with U.S. troops, President Andrzej Duda and Ukrainian refugees, in a bid to signal Western unity against Russia's onslaught.

It comes as the U.K.'s Defense Ministry said Ukraine was pushing Russian troops back and regaining ground near Kyiv.

The Ukraine President Volodymyr Zelenskyy marked one month since Russia launched its full-scale attack by thanking his country's armed forces, suggesting Moscow may not have launched its invasion if it knew the extent of Ukraine's resistance.

U.K. Ministry of Defence says Russians likely to concentrate firepower on urban areas

Local residents retrieve what is left in their destroyed apartments, located in a five-storey residential building that partially collapsed after shelling the day before by Russian troops trying to encircle the Ukrainian capital as part of their slow-moving offensives, in Kyiv on March 20, 2022.
Sergei Supinsky | AFP | Getty Images

The U.K. Ministry of Defence said Russia seems likely to focus its artillery on urban areas.

"Russian forces are proving reluctant to engage in large scale urban infantry operations, rather preferring to rely on the indiscriminate use of air and artillery bombardments in an attempt to demoralise defending forces," the ministry said in its daily intelligence update.

It said, however, this strategy will likely come "at the cost of further civilian casualties" as Moscow looks to "limit its own already considerable losses."

The ministry said Russia's onslaught continues in a number of Ukrainian cities, including Kharkiv, Chernihiv and Mariupol.

— Christine Wang

Pentagon official says Russian forces focusing more on Donbas, less on Kyiv

Service members of pro-Russian troops are seen atop of armoured vehicles in the course of Ukraine-Russia conflict in Dokuchaievsk in the Donetsk region, Ukraine March 25, 2022.
Alexander Ermochenko | Reuters

Russian forces appear to be prioritizing efforts in Donbas in eastern Ukraine, a U.S. Department of Defense official said Friday.

"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," the official said.

While airstrikes on Kyiv continue, the Pentagon official said Russian forces currently do not appear to be pursuing a ground offensive in Ukraine's capital city.

The official also said the Pentagon has seen Russian troop movements in Georgia, which they said could indicate reinforcements may be sent into Ukraine.

Reports of military movements in Ukraine continue to be difficult to confirm as the situation across the country remains fluid and changes rapidly.

The official also confirmed Ukrainian forces destroyed a Russian ship in Berdyansk earlier in the week, but declined to say what weapons were used, in order to protect operational security. The official also said the department does not know how many Russians were onboard when the ship was hit or how many casualties there were.

— Christine Wang

Venture capital fund backed by Russian oligarch removes all traces of operations online

Former Chelsea owner Roman Abramovich looks on from the stands during the Barclays Premier League match between Chelsea and Manchester City at Stamford Bridge on April 16, 2016 in London, England. Abramovich announced on in March 2022 that he was selling the club due to the ongoing situation in Ukraine. The UK government froze Abramovich's assets there days later due to his "close ties with (the) Kremlin."
Paul Gilham | Getty Images

A venture capital fund backed by sanctioned Russian billionaire Roman Abramovich appears to be trying to wipe any trace of its operations since he was sanctioned by the United Kingdom and European Union as the Kremlin wages war on Ukraine.

Impulse VC, an investment fund that has offices in Russia and Germany, has wiped nearly every part of their website that identifies who they are. Their website as of the publication of this story only shows their name "Impulse."

However, a search on the internet archive Wayback Machine shows that in the buildup to the sanctions placed on Abramovich by U.S. allies, the fund's site showed extensive details of its operations and investors, including its portfolio, office locations and target investments in perspective companies.

— Brian Schwartz

Biden compares war scenes in Ukraine to those of 1989 Tiananmen Square protests

President Joe Biden compared images from the Russian invasion of Ukraine to those seen during the famous 1989 protests in Beijing's Tiananmen Square.

Biden made his remarks during a humanitarian aid-focused press conference in Poland, a key stop on his European tour to drum up sustained support for Kyiv and its resistance to Moscow's assault.

"I think even you Poles, who know Ukraine so well, have to be a little surprised at how much courage and capacity and resilience of the Ukrainian people," Biden said. "When you see a 30-year-old woman standing there in front of a tank with a rifle. I mean, talk about what happened in Tiananmen Square. That's Tiananmen Square squared."

The Tiananmen Square protests of 1989 ended in the forcible suppression of pro-democracy demonstrators by the Chinese Communist Party's People's Liberation Army, who had occupied the site. Chinese forces killed and injured thousands in putting down the protests.

Biden appeared to draw a parallel to the most famous image of the protests, which captured a lone man standing in front of a line of tanks.

Thomas Franck

Miles from Ukraine, Biden sees refugee crisis in Poland

US President Joe Biden meets with the President of Poland, Andrzej Duda on March 25, 2022 in Rzeszow, Poland.
Jeff J Mitchell | Getty Images

Just miles from Ukraine, President Joe Biden saluted Poland for giving refuge to more than 2 million refugees who have fled Russia's invasion, then he met with humanitarian experts on the ground about what will be needed to mitigate the growing suffering.

Biden said he had hoped to get even closer to the border but was prevented because of security concerns. Still, he said he wanted to visit Poland to underscore that the assistance it is providing is of "enormous consequence" as Europe experiences the biggest refugee crisis since World War II.

"It's not stopping," Biden said of the devastation in Ukraine. "It's like something out of a science fiction movie."

— Associated Press

We're in a fight between democracy and oligarchs, Biden tells U.S. troops in Poland

US. President Joe Biden disembarks Air Force One at Rzeszow Airport on March 25, 2022 in Rzeszow, Poland.
Omar Marques | Getty Images

U.S. President Joe Biden stopped near Rzeszow, Poland to thank the U.S. Army 82nd Airborne Division ahead of his meeting with the country's President Andrzej Duda in Warsaw.

"We're in the midst of a fight between democracy and oligarchs," Biden said.

U.S. President Joe Biden meets with U.S. Army soldiers assigned to the 82nd Airborne Division at the G2 Arena in Jasionka, near Rzeszow, Poland, March 25, 2022.
Evelyn Hockstein | Reuters

"What's at stake here is not just what we're doing in Ukraine to try to help the Ukrainian people and try to keep the massacre from continuing," Biden said. "Beyond that is what are your kids and grandkids going to look like in terms of their freedom."

U.S. President Joe Biden meets with U.S. Army soldiers assigned to the 82nd Airborne Division at the G2 Arena in Jasionka, near Rzeszow, Poland, March 25, 2022. 
Evelyn Hockstein | Reuters

"What you're engaging in is much bigger than whether or not you can alleviate the pain and suffering of the people of Ukraine. We're in a new phase, we're at an inflection point," he said. Biden added that the world will not be the same in 10 or 15 years and the question is: "Who's going to prevail," democracy or autocracy.

U.S. President Joe Biden takes a selfie with U.S. Army soldiers assigned to the 82nd Airborne Division at the G2 Arena in Jasionka, near Rzeszow, Poland, March 25, 2022. 
Evelyn Hockstein | Reuters

"You are the finest fighting force in the history of the world," Biden said.

U.S. President Joe Biden eats pizza as he meets with U.S. Army soldiers assigned to the 82nd Airborne Division at the G2 Arena in Jasionka, near Rzeszow, Poland, March 25, 2022. 
Evelyn Hockstein | Reuters

In addressing the troops, Biden invoked his son Beau Biden, a lawyer and officer in the Army Judge Advocate General's Corps who served in Iraq and Kosovo.

"There are hundreds of thousands of people like my son, like all of you. So thank you, thank you, thank you, thank you," Biden said.

US President Joe Biden (L) takes a selfie photo as he meets service members from the 82nd Airborne Division, who are contributing alongside Polish Allies to deterrence on the Alliances Eastern Flank, in the city of Rzeszow in southeastern Poland, around 100 kilometres (62 miles) from the border with Ukraine, on March 25, 2022.
Brendan Smialowski | AFP | Getty Images

— Dawn Kopecki, Getty Images/Reuters

U.S. Treasury Secretary Yellen says China sanctions are not needed right now

Treasury Secretary Janet Yellen told CNBC on Friday that she does not see reason to impose economic sanctions against China now as the U.S. works to stifle aid to Russia.

The U.S. and its NATO allies have for weeks warned Beijing that efforts to outfit Moscow with arms or provide economic relief in violation of Western sanctions would result in unspecified consequences.

China has thus far refused to denounce Russia's assault on Ukraine, and U.S. officials say that Russia has asked Beijing for help as it struggles to seize control of its neighbor.

"We would be very concerned if they were to supply weapons to Russia, or to try to evade the sanctions that we've put in place on the Russian financial system and the central bank," Yellen said of China. "We don't see that happening at this point."

Thomas Franck

Yellen says Russian oligarch Abramovich 'could face sanctions' by U.S.

Chelsea owner Roman Abramovich looks on after their 3-1 win in the Barclays Premier League match between Chelsea and Sunderland at Stamford Bridge on December 19, 2015 in London, England.
Clive Mason | Getty Images

Treasury Secretary Janet Yellen said Russian billionaire Roman Abramovich "could face sanctions" from the U.S., despite his claims of being a peace-broker between Ukraine and Russia.

Abramovich, the highest profile oligarch in the West, has been sanctioned by the U.K., European Union and Canada. But questions have swirled around why the U.S. has been slow to act. Ukraine's President Volodymyr Zelensky advised President Biden to hold off sanctioning Abramovich, who he said could act as a go-between with Russia to negotiate peace, according to The Wall Street Journal.

Secretary Yellen told CNBC that Abramovich could still face sanctions.

"I would hold open the possibility that — certainly not take off the table the possibility — he or other individuals could face sanctions in the future," she said.

— Robert Frank

Polish president's plane makes emergency landing in Warsaw

Polish President Andrzej Duda.
Artur Widak | NurPhoto | Getty Images

The airplane carrying Polish President Andrzej Duda to meet U.S. President Joe Biden in eastern Poland has made an emergency landing after returning to Warsaw, Duda's advisor Jakub Kumoch was cited as saying by state-run news agency PAP on Friday.

The head of Duda's office, Pawel Szrot, told Reuters that the Polish president did not face any danger.

— Reuters

Biden to meet Ukrainian refugees, give 'major address' on Saturday

A U.S. support plane lands at Rzeszow-Jasionka Airport ahead of U.S. President Joe Biden arrival to visit Poland, amid Russia's invasion of Ukraine, near Rzeszow, Poland, March 25, 2022.
Kacper Pempel | Reuters

President Joe Biden will travel to Warsaw, Poland, on Saturday to meet with Ukrainian refugees and Americans providing humanitarian aid before delivering a "major address," the White House said.

Biden's speech "will speak to the stakes of this moment, the urgency of the challenge that lies ahead, what the conflict in Ukraine means for the world, and why it is so important that the free world sustain unity and resolve in the face of Russian aggression," national security advisor Jake Sullivan told reporters on Air Force One.

"He'll also talk about the context and history of this conflict, and where he sees it going from here," Sullivan said.

The president will give the speech Saturday afternoon before boarding his flight back to the U.S., Sullivan said.

Biden will also meet with Polish President Andrzej Duda on Ukraine's western border that has