US President Joe Biden wrapped up a four-day trip to Europe on Saturday, holding talks with Polish President Andrzej Duda, meeting with Ukrainian refugees and delivering a capstone speech in Warsaw.

During his address, Biden declared that Russian "cannot remain in power." The White House later clarified that he wasn't calling for regime change, saying the President's point was that "Putin cannot be allowed to exercise power over his neighbors or the region."

Earlier this week, Biden attended a trio of last-minute summits in Belgium dedicated to the crisis in Ukraine. He announced new punishment directed at members of Russia's parliament, and he unveiled a plan for the US to accept as many as 100,000 Ukrainian refugees.

The trip was one of the highest-stakes presidential trips in recent memory, offering Biden a chance to assume leadership of a newly united West.

Biden arrives at the Royal Castle to speak about the Russian invasion of Ukraine on Saturday evening.
Biden arrives at the Royal Castle to speak about the Russian invasion of Ukraine on Saturday evening.
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Biden meets with Ukrainian refugees and humanitarian aid workers in Warsaw on Saturday.
Biden meets with Ukrainian refugees and humanitarian aid workers in Warsaw on Saturday.
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Biden meets with Polish President Andrzej Duda, far right, at the Presidential Palace in Warsaw on Saturday.
Biden meets with Polish President Andrzej Duda, far right, at the Presidential Palace in Warsaw on Saturday.
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Biden speaks with Duda as he arrives at the Presidential Palace on Saturday.
Biden speaks with Duda as he arrives at the Presidential Palace on Saturday.
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Biden speaks to members of the US Army in Jasionka, Poland, on Friday, March 25.
Biden speaks to members of the US Army in Jasionka, Poland, on Friday, March 25.
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Biden and Polish President Andrzej Duda participate in a roundtable discussion Friday about the humanitarian response following Russia's invasion of Ukraine.
Biden and Polish President Andrzej Duda participate in a roundtable discussion Friday about the humanitarian response following Russia's invasion of Ukraine.
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Biden takes a selfie with US service members in Poland on Friday.
Biden takes a selfie with US service members in Poland on Friday.
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Biden eats a slice of pizza while meeting with members of the 82nd Airborne Division.
Biden eats a slice of pizza while meeting with members of the 82nd Airborne Division.
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Biden holds a news conference in Brussels, Belgium, on Friday before leaving for Poland. Speaking alongside European Commission President Ursula von der Leyen, Biden said Russia was using its supply of oil and gas to "coerce and manipulate its neighbors." He said the United States would help Europe reduce its dependence on Russian oil and gas and would ensure the continent had enough supplies for the next two winters.
Biden holds a news conference in Brussels, Belgium, on Friday before leaving for Poland. Speaking alongside European Commission President Ursula von der Leyen, Biden said Russia was using its supply of oil and gas to "coerce and manipulate its neighbors." He said the United States would help Europe reduce its dependence on Russian oil and gas and would ensure the continent had enough supplies for the next two winters.
Evan Vucci/AP
Ukrainian President Volodymyr Zelensky addresses Biden and other world leaders via video at the NATO summit in Brussels on Thursday. Zelensky stopped short of issuing his usual request for a no-fly zone, but he did say Ukraine needs fighter jets, tanks and better air defenses.
Ukrainian President Volodymyr Zelensky addresses Biden and other world leaders via video at the NATO summit in Brussels on Thursday. Zelensky stopped short of issuing his usual request for a no-fly zone, but he did say Ukraine needs fighter jets, tanks and better air defenses.
Denzel/Bundesregierung/Handout/Getty Images
"NATO has never, never been more united than it is today," Biden said at a news conference in Brussels on Thursday. "(Russian President Vladimir) Putin is getting exactly the opposite of what he intended to have as a consequence of going into Ukraine."
"NATO has never, never been more united than it is today," Biden said at a news conference in Brussels on Thursday. "(Russian President Vladimir) Putin is getting exactly the opposite of what he intended to have as a consequence of going into Ukraine."
Evan Vucci/AP
Biden and other world leaders pose for a group picture at the NATO summit on Thursday. Biden is in the front row, third from right.
Biden and other world leaders pose for a group picture at the NATO summit on Thursday. Biden is in the front row, third from right.
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Biden is seated second from left as NATO Secretary General Jens Stoltenberg speaks at the NATO summit. "We gather at a critical time for our security," Stoltenberg said as the meeting convened. "We are determined to continue to impose costs on Russia to bring about an end to this brutal war."
Biden is seated second from left as NATO Secretary General Jens Stoltenberg speaks at the NATO summit. "We gather at a critical time for our security," Stoltenberg said as the meeting convened. "We are determined to continue to impose costs on Russia to bring about an end to this brutal war."
Evelyn Hockstein/AP
Biden is greeted by Belgian Prime Minister Alexander de Croo after arriving in Brussels on Wednesday.
Biden is greeted by Belgian Prime Minister Alexander de Croo after arriving in Brussels on Wednesday.
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Marine One lifts off from the South Lawn of the White House as Biden begins traveling on Wednesday.
Marine One lifts off from the South Lawn of the White House as Biden begins traveling on Wednesday.
Patrick Semansky/AP
Biden speaks with members of the press before boarding Marine One on Wednesday. Asked what he'd say to his partners in Europe, Biden said he'd wait to deliver his message face to face.
Biden speaks with members of the press before boarding Marine One on Wednesday. Asked what he'd say to his partners in Europe, Biden said he'd wait to deliver his message face to face.
Patrick Semansky/AP