President Biden addressed the group of European nations known as the Bucharest Nine on Wednesday, stressing the need to stand up to Russian aggression and emphasizing the United States' commitment to NATO allies.

Biden's appearance at the Bucharest Nine meeting in Warsaw came as part of a European tour that saw the president stop in Ukraine and meet with President Volodymyr Zelenskyy before heading to Poland. The trip is taking place nearly one year to the day after Russia invaded Ukraine, kicking off a war that continues to rage on.

"As NATO’s eastern flank, you’re our front lines of our collective defense and you know better than anyone what’s at stake in this conflict," Biden said to officials from the B9 countries of Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, and Slovakia.

While pointing out the other nations' role in fending off a Russian threat, Biden made it perfectly clear that the U.S. will be there with them if any NATO member is attacked.

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"The commitment of the United States to NATO – I’ve said it to you many times and I’ll say it again, – is absolutely clear. Article 5 is a sacred commitment the United States has made," Biden said. "We will defend literally every inch of NATO. Every inch of NATO."

Article 5 of the NATO treaty says that "an armed attack against one or more" member countries "shall be considered an attack against them all," and that each member "will assist the Party or Parties so attacked by taking forthwith … such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area."

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Biden said that with Russia continuing its offensive, "what literally is at stake is not just Ukraine, it's freedom."

Following Biden's remarks, NATO Secretary General Jens Stoltenberg claimed that Russian President Vladimir Putin is showing no signs of slowing down or seeking peace, but "is preparing for world war."

President Joe Biden delivered a speech marking the one-year anniversary of the Russian invasion of Ukraine. (WHD Photo/ Evan Vucci)

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"So we must sustain and step up our support for Ukraine," Stoltenberg continued." We must give Ukraine what they need to prevail. We don’t know when the war will end, but when it does, we need to ensure that history does not repeat itself."