The United Nations and the International Committee of the Red Cross began evacuating civilians from the besieged southern port city of Mariupol, and the operation will continue on Monday.

“The Mariupol humanitarian operation will continue until we achieve our goals — saving the lives of our citizens,” Iryna Vereshyuk, Ukraine’s deputy prime minster, said in a message she posted on Telegram, according to an NBC News translation. Around 100 civilians have been rescued so far, Ukrainian President Volodymyr Zelenskyy said.

A few thousand civilians and Ukrainian fighters have been holed up in the sprawling Azovstal steel plant in Mariupol, and about 100,000 people still remain in Mariupol, officials have said.

Zelenskyy met with U.S. House Speaker Nancy Pelosi and a Congressional delegation in Kyiv. He called the U.S. a “leader in strong support” for Ukraine. The delegation praised the courage of the Ukrainian people during a visit to Poland. Pelosi vowed that Washington would stand with the country until it defeats Russia.