President Biden is traveling to Brussels on Wednesday to take part in a special NATO summit in Belgium and visit Poland to discuss international efforts to support Ukraine and punish Russia for its invasion.
The trip comes after Biden said there will be a "new world order" that must be led by the United States.
Departing the White House Wednesday morning, Biden was asked what he will say to European partners.
"I'm going to say it all to their face," Biden told reporters. "I'll be happy to talk to you guys when I get back."
Biden, was also asked about chemical warfare, to which he replied: "I think it's a real threat."
During the summit, Biden will "discuss the ongoing deterrence and defense efforts in response to Russia’s unprovoked and unjustified attack on Ukraine as well as to reaffirm our ironclad commitment to our NATO allies," the White House said.
Biden, after the summit, is scheduled to join a European Council Summit to discuss "shared concerns about Ukraine, including transatlantic efforts to impose economic costs on Russia, provide humanitarian support to those effected by the violence, and to address other challenges related to the conflict."
Following his meetings in Brussels with NATO allies, G7 leaders and European Union Leaders, Biden will travel to Warsaw, Poland, on March 25, where he will hold a bilateral meeting with President Andrzej Duda.
Biden on Friday is expected to discuss how the United States and allies are responding to the humanitarian and human rights crisis that Russia’s war on Ukraine has created.
White House National Security Advisor Jake Sullivan, last week, spoke with the secretary of the Russian Security Council, Gen. Nikolay Patrushev, and called for Russia to "stop attacking" Ukrainian cities and towns, while warning of "consequences" should Russia decide to use any chemical or biological weapons on Ukraine.
Sullivan's warnings about Russia's possible use of chemical weapons comes after the White House warned that Russia could use "chemical or biological weapons in Ukraine" or could create a "false flag operation" using them, after the Kremlin accused the U.S. of being involved in biological weapons research at Ukrainian labs.
But Biden warned on Monday that the world is "at an inflection point," one that "occurs every three or four generations."
"As one of — as one of the top military people said to me in a secure meeting the other day, 60 — 60 million people died between 1900 and 1946," Biden said. "And since then, we’ve established a liberal world order, and that hadn’t happened in a long while."
Biden warned that now is a time "when things are shifting."
"We’re going to — there’s going to be a new world order out there, and we’ve got to lead it," Biden said. "And we’ve got to unite the rest of the free world in doing it."
The Biden administration has voiced "deep concerns" about Russia’s "alignment" with China, as intelligence officials said that the Kremlin had turned to Beijing for economic and military aid after its invasion of Ukraine on Feb. 24.
The president had a secure video call with Chinese President Xi last week for nearly two hours in which he warned of the "consequences" should China "provide material support" to Russia amid its multi-front war on Ukraine.
White House national security adviser Jake Sullivan, who met with his Chinese counterpart in Rome, Italy, last week ahead of Biden and Xi’s meeting, said that the administration "has not seen" the "provision of military equipment by China to Russia" in the days since Biden’s meeting.
"But of course, this is something we are monitoring closely," Sullivan said Tuesday. "We will continue to monitor it."
Sullivan added that Biden "made clear to President Xi the implications and consequences of any such provision of equipment, and they very well understand one another."
Meanwhile, Russian troops continue to shell the strategic port city of Mariupol this week as troops remained largely stalled outside of Kyiv. Thousands of Mariupol residents escaped on Tuesday while Russia continued to bomb the city.
A senior U.S. defense official said that Defense Secretary Lloyd Austin is still considering the possibility of deploying additional American troops to NATO's eastern flank in Europe.
Ukrainian President Volodymyr Zelenskyy issued a statement ahead of the NATO and G7 summits, saying there are about 100,000 people in Mairupol in "inhuman conditions, in a complete blockade," and with "no food, no water, no medicine," saying they are "under constant shelling, under constant bombing."
"For more than a week now we have been trying to organize stable humanitarian corridors for Mariupol residents. And almost all our attempts, unfortunately, are disrupted by the Russian occupiers. By shelling or deliberate terror," Zelenskyy said
"We continue to work at various levels to force Russia to peace. To the end of this brutal war. Ukrainian representatives are working on the negotiations, which continue virtually every day," Zelenksyy continued. "It's very difficult. Sometimes scandalous. But step by step we are moving forward."
"We will work, we will fight in any way we can. Till the end. Bravely and openly. At all these sites. With full energy."
But on Tuesday, spokesman for Russian President Vladimir Putin, Dmitri Peskov, refused Tuesday to say Russia would not use nuclear weapons if it thought Russia could be destroyed.
Peskov said the conditions were consistent with the nation's national security concept.
"If there’s a threat to the very existence of our country, it can be used in accordance with this concept," he stated in response to the question of whether Russia’s use of nuclear weapons could be completely ruled out, according to the Russian government-controlled news site TASS.
"Russian military doctrine envisions use of nuclear weapons in a first-use scenario if it is losing a conventional conflict. Ukraine is exactly the scenario for which this was developed," said Rebekah Koffler, a former DIA intelligence officer who specialized in Russia.
"They fear U.S. intervention in Ukraine because they fear we are conventionally superior," she said. "And if they interpret our action as offensive rather than defensive, that is when the viability of Russian statehood would be threatened, in accordance with the Russian national security concept and military doctrine."
Fox News' Greg Norman and The Associated Press contributed to this report.