On a visit to neighboring Romania on Saturday, US First Lady Jill Biden praised the “very strong” migrants fleeing war-torn Ukraine.

“You are amazingly strong,” Biden said after listening women and children recount their experiences fleeing Russia’s assault of their country.

“We stand with you, I hope you know that,” she said in a visit to a school in Bucharest, accompanied by her Romanian counterpart Carmen Iohannis, according to images transmitted by TVR public television.

More than 810,000 Ukrainians have entered Romania since the start of the war, according to UN figures released on April 29.

Most have moved on to other countries, with an estimated 80,000 staying, half of them children, according to the World Vision foundation.

Biden’s visit to the region is the latest show of US support for Ukraine and the countries assisting it, and follows a trip to Kyiv by US House Speaker Nancy Pelosi, who met with President Volodymyr Zelensky a week ago.

On Friday Biden met with US service members in Romania and on Sunday, she is set to travel to Slovakia, where she will meet with refugees, aid workers and local residents in the city of Kosice and the village of Vysne Nemecke.

She will also travel to the Slovak capital Bratislava to meet with US embassy staff and government officials.

Nearly 5.5 million refugees have fled Ukraine since Russian President Vladimir Putin launched his invasion on February 24, according to the UN.

According to UN data, almost 360,000 of them have crossed the border into Slovakia.

US Vice President Joe Biden recommended a $33 billion proposal to arm and help Ukraine.