President Joe Biden said the world has responded to a "test for the ages" amid heightened tensions between the U.S. and Russia as he marked the one-year anniversary of Russia’s invasion of Ukraine.

Biden, in a speech outside the Kubicki Arcades palace in Warsaw, said Russian President Vladimir Putin thought Ukraine would "roll over" when he invaded, but "he was wrong" because of the "iron will" of Ukrainians and nations everywhere.

"One year ago, the world was bracing for the fall of Kyiv," Biden said. "Well, I just came from visiting Kyiv, and I can report, Kyiv stands strong. Kyiv stands proud. It stands tall, and most importantly, it stands free."

Autocrats like Putin, Biden said, understand only one word: "No, No, No." But the democracies of the world have gotten stronger while autocrats have gotten weaker, he declared.

The message of solidarity– delivered in front of U.S., Poland and Ukraine flags – came shortly after Russian President Vladimir Putin said Russia will pull back from the New START nuclear treaty in response to a surprise visit Biden made Monday to Kyiv, Ukraine’s capital.

Biden says Article V of NATO alliance remains 'rock solid'

Biden’s three-day trip to Poland comes as Russia has started what is expected to be a fierce spring assault in Ukraine. Although Biden announced new assistance to  the war-ravaged ally, the trip also comes as polls show support softening among the American public for providing Ukraine with taxpayer-funded weaponry and direct assistance.

Biden addressed the people of Russia, telling them the “war was never a necessity” as he pushed back against Putin’s remarks made in a speech earlier Tuesday. “Putin chose this war. For every day the war continues, it is his choice.”

He said Poland and the U.S. would be announcing new sanctions against Russia this week holding Putin accountable for “crimes against humanity.” He also declared “rock solid” the U.S.’s participation in the mutual defense commitment of countries in the NATO alliance.

“Every member of NATO knows it. Russia knows it as well. An attack against one is an attack against all,” Biden said.

Ahead of his remarks, Biden held a bilateral meeting with Polish President Andrzej Duda. In remarks ahead of the bilateral meeting, Biden highlighted his visit to Poland last year, saying that "a year later that NATO is stronger than it’s ever been."

"The United States needs Poland and NATO as much as Poland and NATO need the United States," Biden said.

Duda in his opening remarks praised Biden's surprise trip to Kyiv, saying that it's "a sign that a free world has not forgotten them."

"This visit is crucially important, it is a symbolic visit here to our region," Duda said, according to a translator. "The United States of America carries constantly the responsibility for the security of Europe and the world."

The latest

• More aid to Ukraine: During his visit to Kyiv, Biden announced roughly half a billion dollars in additional security assistance to Ukraine. The package would include more military equipment, including artillery ammunition; more Javelins, an anti-tank missile system; and howitzers, or long-range artillery weapons, Biden said.

• What’s on Biden’s agenda? Biden on Tuesday met with Duda to discuss his nation's logistical role in getting military aid to Ukraine and collective efforts to bolster deterrence efforts among the NATO alliance. He also plans to meet Wednesday with allies on NATO’s eastern flank to reaffirm U.S. support for the security of the alliance.

• Second visit to Poland: This is Biden’s second visit to Poland in less than a year. He traveled to the country last March, just weeks after the war in Ukraine began to present a united front with U.S. allies against Russian aggression. At the time, he met with Ukrainian refugees during that trip.

Takeaways

The president’s visit to Kyiv and Poland this week  came just days ahead of the one-year anniversary of Russia’s invasion of the former Soviet republic — which has triggered the largest conflict in Europe since World War II.

During his visit to Ukraine which Russia first invaded on Feb. 24, 2022, Biden highlighted the United States support of the country and vowed to continue to provide supportfor the duration of the war.

And he delivered a similar message in Poland, highlighting how the United States has rallied international support around Ukraine and punished Russia for its aggression.

“One year into this war, Putin no longer doubts the strength of our coalition. But he still doubts our conviction," Biden said. "But there should be no doubt. Our support for Ukraine will not waiver."

Putin’s combative speech

Ahead of Biden’s speech Tuesday, Putin gave his own address ahead of the anniversary of the Russian invasion.

Putin announced that he was suspending Moscow's participation in New START – a strategic nuclear arms reduction treaty between the U.S. and Russia. He attributed the action to the U.S. and NATO, but did not add any specifics.

The move signals that Russia’s war with its neighbor will continue as the United States has vowed to supply Ukraine with aid and weapons as long as conflict goes on.

National Security Advisor Jake Sullivan in a call with reporters declined to comment on Putin's speech, as it was ongoing at the time. But he said Biden's speech "is not a rhetorical contest with anyone else."

"This is an affirmative statement of values, a vision for what the world we're both trying to build and defend should look like," Sullivan said.

Sullivan added that Biden's speech would not be a rebuttal but "rather to lay to rest an argument that Russia has been making for some time" that the United States and the West has caused the war.

"The President will take that argument on quite directly and emphatically," Sullivan said.

Want to know more? Here's what you missed

BIDEN MAKES SURPRISE UKRAINE STOP: Joe Biden walks streets of Kyiv in surprise visit: 'Americans stand with you'

INSIDE BIDEN'S SECRET KYIV TRIP: How President Biden pulled off a secret trip to Ukraine one year into Russia's war

UKRAINE REFUGEES UNSURE WHEN THEY'LL GO HOME: They counted the days until they could return to Ukraine. Now, they're not sure they'll go back

AMERICANS GROW WEARY OF WAR IN UKRAINE: Support for providing weapons to Ukraine fading in US

WHERE IS UKRAINE WAR AID GOING?: US has spent billions on Ukraine war aid. But is that money landing in corrupt pockets?

Contributing: Kim Hjelmgaard

This article originally appeared on USA TODAY: Biden speech livestream: Biden in Poland marks Russia Ukraine war