President Joe Biden traveled to Poland on Friday to get a first-hand look at the massive humanitarian effort required to take care of millions of Ukrainian refugees who have flowed into Eastern Europe.

In Rzeszow – about fifty miles from Poland’s border with Ukraine – Biden met with the Army’s 82nd Airborne Division, part of the U.S.’s recently bolstered military presence in the region. The president shared a pizza pie with soldiers and teased them about their close-cropped haircuts. He also shared a story about his deceased son Beau, who was a major in the Delaware Army National Guard.

Biden called the soldiers “the finest fighting force in the history of the world” and added, “I personally thank you for what you do.”

The Associated Press adds:

He later addressed a group of soldiers in more formal remarks, telling them the nation “owes you big.” Biden also borrowed the words of the late Secretary of State Madeline Albright to underscore their place in a fragile moment for the U.S. and its European allies.

“The secretary of state used to have an expression. She said, ‘We are the essential nation,’” Biden told the troops. “I don’t want to sound philosophical here, but you are in midst of a fight between democracy and an an oligarch.”

He will be in Warsaw on Saturday for talks with Polish President Andrzej Duda and others. The Polish leader was to welcome Biden at the airport on Friday, but his plane was delayed by a technical problem.

Duda eventually attended a humanitarian briefing with Biden. The U.S president said he’s disappointed that he’s unable to travel into Ukraine.

“Quite frankly, part of my disappointment is that I can’t see it firsthand like I have in other places,” Biden said. “They will not let me — understandably, I guess — cross the border and take a look at what’s going on in Ukraine.”

The Washington Post adds:

Biden praised Duda and the Polish people for their work to assist in the humanitarian crisis and touted the West’s unity in opposing Russian aggression.

“The single most important thing that we can do from the outset is keep the democracies united in our opposition, and our effort to curtail devastation that is occurring at the hands of a man who quite frankly I think is a war criminal,” Biden said.

Duda said 2.5 million Ukrainians have crossed into Poland since Russia invaded the country late last month.

Duda described the refugees as “our guests, our brothers, our neighbors from Ukraine who today are in a very difficult situation.” 

He reiterated Biden’s message that the West must remain unified.

Biden plans to travel to Warsaw on Saturday to meet with Ukrainian refugees.