It will mark the conclusion of Biden’s whirlwind trip leading up to the one-year anniversary of the war in Ukraine that included a visit to the U.S. Embassy in Warsaw Tuesday and a historic surprise visit to Ukraine’s capital of Kyiv.

On Tuesday, Biden gave an unwavering sign of support for Ukraine and countries like Poland that have supported the government of its President Volodymyr Zelensky as they weathered the invasion of Russia, which has reached the one-year mark.

“He thought NATO would fracture and divide,” Biden said Tuesday evening in front of a cheering crowd in Warsaw. “Instead, NATO is more united and more unified than ever before. He thought he could weaponize energy to crack your resolve — Europe’s resolve. Instead, we’re working together to end Europe’s dependence on Russian fossil fuels.”

Biden had announced Tuesday that the United States would host NATO’s 75th-anniversary summit next year. He said NATO is the “strongest defensive alliance in the history of the world.”

The Bucharest Nine is made up of Bulgaria, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia. The countries formed an alliance a year after Russia forcibly annexed Crimea from Ukraine in 2014.

Biden’s meeting with the nation comes as Russian President Vladimir Putin in his State of the Nation address announced that Russia would suspend its participationin the New START nuclear arms treaty — the last remaining arms control agreement it had with the United States.

In the address before Biden’s Poland speech blamed the Ukrainian war on the United States and its western allies. He said Russia had no choice but to invade Ukraine to protect its own borders.

Biden directly responded to the criticism in his speech, calling the invasion a war of choice for Putin and Russia and they could end it at any time.

Biden is expected to return to the White House Wednesday night after leaving Warsaw Chopin International Airport in Warsaw at the conclusion of the meeting.