MIHAIL KOGALNICEANU AIR BASE, Romania >> Delivering good cheer — and gallons of ketchup — Jill Biden today thanked U.S. troops deployed to Romania for serving as a check against Russian aggression as she opened a two-country European trip to learn about the refugee crisis caused by Moscow’s invasion of Ukraine.

The U.S. first lady flew overnight from Washington and landed just in time to help serve dinner at Romania’s Mihail Kogalniceanu Air Base near the Black Sea and about 60 miles (100 kilometers) from the border with Ukraine. The base is temporarily home to about 1,600 of the several thousand troops President Joe Biden deployed to Eastern Europe in the leadup to the Russia-Ukraine war.

In the food line, Jill Biden dished up macaroni and cheese and baked potatoes — and encouraged fatigue-clad troops to have some greens, too — before she greeted groups of them as they ate at round tables in the dining hall. They cheered when she revealed she came bearing ketchup, which was in short supply on the base.

“I know it’s hard on your families,” she told one servicemember, referencing her own experience when her son Beau Biden deployed to Iraq.

At another location on the base, the first lady joined Staff Sgt. Sharon Rogers to read the children’s book “Night Catch” on videotape for Rogers’ son, Nathan, who lives in Texas. Biden thanked the boy for serving his country, too.

“When your mom serves, the family serves, too, so thank you for your service,” she told Nathan. She and Rogers embraced and Biden wished her a happy Mother’s Day.

Before leaving the base and flying to Bucharest, Romania’s capital, the first lady posed with troops who represent her home state through their service in the Delaware Army National Guard. She handed them a souvenir coin she designed, the first time she’d given away copies of the coin.

For weeks, the first lady has been transfixed by the news coming out of Ukraine, by the bombings and scenes of “parents weeping over their children’s broken bodies in the streets,” as she said in a recent speech. She’s now using her second solo overseas trip to experience the crisis for herself by visiting Romania and Slovakia.

“It’s so important to the president and to me that the Ukrainian people know that we stand with them,” Biden told reporters Thursday night before she departed Washington.

NATO allies Romania and Slovakia border Ukraine and have taken in some of the millions of mostly women and children who fled after Russia invaded Ukraine in late February, triggering Europe’s largest refugee crisis since World War II.

Biden is also using the trip to highlight issues she promotes at home, including support for U.S. service members, education and the welfare of children.

The centerpiece of the trip comes Sunday — Mother’s Day — when the mother of three meets with displaced Ukrainians who sought refuge across the border in Slovakia.

Her daughter, Ashley Biden, had planned to accompany her, but backed out Thursday after learning that she was a close contact of someone who tested positive for COVID-19, said Michael LaRosa, the first lady’s spokesperson. Ashley Biden tested negative, he said.

The first lady also will meet during the trip with humanitarian aid workers, educators, government officials and U.S. embassy personnel, the White House said.

Nearly 6 million Ukrainians, mostly women and children, have fled their country since Russia’s invasion, according to the U.N. refugee agency. Hundreds of thousands have resettled in next-door countries, like Romania and Slovakia, or have gone elsewhere in Europe to rebuild their lives.

Biden has long shown an interest in the plight of refugees around the world.

In 2011, when her husband was vice president, she traveled to drought-stricken east Africa to visit with Somali famine refugees at the Dadaab camp in Kenya. In 2017, she visited refugees in Chios, Greece, as part of work by the aid organization Save The Children, on whose board she served.

Some refugee advocates said Biden’s trip will send the message that the United States takes seriously its humanitarian commitment to the Ukrainian people.

“Every first lady has a far-reaching platform to raise awareness and this trip will be an important tool for mobilizing additional support for those forced to flee their homeland,” said Krish O’Mara Vignarajah, president and CEO of Lutheran Immigration and Refugee Service and formerly a policy director to first lady Michelle Obama.

Biden’s trip follows other U.S. government representatives visiting Kyiv, Ukraine’s capital, to meet with President Volodymyr Zelenskyy, including House Speaker Nancy Pelosi, Defense Secretary Lloyd Austin and Secretary of State Antony Blinken.

President Biden visited Ukrainian refugees in March during a stop in Poland, the closest he’s been to Ukraine during the war. The White House says there are no plans for him to visit Kyiv.

Jill Biden continues her trip Saturday in Bucharest with briefings on the humanitarian efforts, meeting with Romanian first lady Carmen Iohannis and touring a school where Ukrainian refugee students are enrolled. The first lady is a community college English professor.

On Sunday in Slovakia, Biden will visit a city-operated refugee center and a public school in Kosice that also hosts Ukrainian refugee students to participate in Mother’s Day events with Ukrainian and Slovakian mothers and children. She’ll also visit the Slovakia-Ukraine border crossing in Vysne Nemecke, Slovakia.

The White House declined to comment on whether she will cross the border and enter Ukraine.

Monday brings a meeting with Slovakian President Zuzana Caputova, the country’s first female president, before Biden heads back to Washington.