As he begins the final day of a high-stakes international tour, Biden meets with Ukrainian leaders in Poland.

Poland's capital is Warsaw. (CNN)President Joe Biden met with Ukrainian officials in Warsaw, Poland, on Saturday, as part of a last-minute tour to Europe aimed at coordinating how Western allies will respond to Russia's aggression and assuring states that the US stands by them.

The focus of Biden's trip to Europe has been solely on the war. However, Biden's meetings with Foreign Minister Dmytro Kuleba and Defense Minister Oleksii Reznikov were the first face-to-face meetings he had with Ukrainian officials during his tour.

Kuleba began the discussion by recounting an exhausting travel from Kyiv to Warsaw that involved a train ride and three hours in a car.

"It's like taking a flight from Kyiv to Washington with a stopover in Istanbul," Kuleba explained. "The good news is that I've learnt to sleep in any situation since the beginning of the war. As a result, I slept on the train and in the automobile."

Hearing how the pastors had traveled, Biden shared that he, too, had taken many train trips.

"You're looking at a man who has ridden a train for over a million, 200,000 miles. Quite literally, "Biden stated the following. As a senator and vice president, Biden rode Amtrak trains from his home in Delaware to Washington. 

The delegation, which included Secretary of State Antony Blinken and Defense Secretary Lloyd Austin and met at a hotel in Warsaw, was expected to discuss more substantial matters later. Ukraine has been urging the US and NATO to enhance military aid, with President Volodymyr Zelensky calling for a no-fly zone to be established.

After negotiations in Brussels this week, during which Zelensky was virtually present, it appeared that NATO members were not enthusiastic about the notion. Biden has stated that getting more involved in the conflict could lead to World War III.

Ukraine's leaders were shocked by this. "To be honest, we are quite dissatisfied. More boldness is expected. Some daring decisions were expected. The alliance has made decisions as if there isn't a war going on "In a live interview with the Atlantic Council on Friday, Andriy Yermak, the head of Ukraine's President's Office, said.

Biden will meet with Ukrainian refugees and hold a bilateral discussion with Polish President Andrzej Duda in Warsaw to discuss how the US and its allies are reacting to the refugee issue that has arisen as a result of the war. Before returning to Washington, the President will give a "big address," according to the White House.

"The stakes of this moment, the urgency of the challenge that lies ahead, what the conflict in Ukraine means for the world, and why it is so important that the free world sustain unity and resolve in the face of Russian aggression," White House national security adviser Jake Sullivan said in a preview on Friday.

Biden's multi-day trip through Europe began in Brussels, where he met with key US allies to discuss the war's worldwide response. The journey will conclude in a country bordering Ukraine, where regional security challenges and the ongoing humanitarian catastrophe will be front and center.

Biden announced new sanctions against Russian parliament members during snap summits in Brussels, revealed the US' intention to take in 100,000 refugees fleeing Ukraine, and conferred with world leaders on how the world will respond if Russia uses chemical, biological, or nuclear weapons during the conflict.

Biden also unveiled a new plan on Friday aimed at depriving Russian President Vladimir Putin of European energy riches, which he claims are being used to fund Russia's war in Ukraine. Later that day, after arriving 65 miles from Poland's Ukrainian border, the President met with aid workers to hear about their experiences helping to alleviate the humanitarian crisis, as well as members of the 82nd Airborne Division, who have been stationed along NATO's eastern edge to deter potential Russian aggression.

"What you're engaged in is much more than whether or not we can ease the misery of Ukraine," Biden told the service personnel on Friday.

"Your generation is entering a new era. We've arrived at a crossroads, "he stated He also explained to the troops that their duty entailed more than just conveying a message to Russia. Instead, he claimed, they were sending a message to all autocrats around the world.

While Biden will meet with refugees in Warsaw, he stated on Friday that he would want to get a closer look at the problem.

"They won't allow me cross the border and look at what's going on in Ukraine," he continued, "which is understandable." The White House has stated that a visit to Ukraine is not being considered.

The visit to Ukraine's western neighbor comes as Poland has pressed the US to engage more in the battle on numerous fronts.

Duda, for example, has requested that the United States expedite and simplify the procedures for allowing Ukrainians with family in the United States to enter the country.

According to United Nations refugee agency figures released on Tuesday, more than 3.5 million people have fled Ukraine. The vast majority of those displaced people have fled to Ukraine's western European neighbors.

Poland, which shares a western border with Ukraine, has registered more than 2 million Ukrainian refugees, albeit not all of them have remained in the nation.

In addition, the US has continued to reject Poland's offer to help Ukraine transfer its MiG-29 fighter fighters. Furthermore, the Polish President has asked for a more permanent NATO defense posture in Poland, as well as an international peacekeeping mission in Ukraine.

Officials in the United States have expressed skepticism about the peacekeeping proposal, claiming that it would go against Biden's red line of keeping US soldiers out of the fight.

Duda said Biden's "being here sends a fantastic signal and evidence of togetherness — unity inside NATO" at a meeting with humanitarian workers on Friday.

Biden's visit, according to the Polish President, "demonstrates a huge support and also a big significance attached by the United States to the stability and world peace, to reinstating the peace where difficult situations arise in places where someone resorts to acts of aggression against other democratic and free nations — as it is happening today against Ukraine, where Russian aggression has been in effect for a month now."

This story was co-written by CNN's Kevin Liptak and Sam Fossum.