Ukrainian officials said they expect more civilians will be able to evacuate from the besieged city of Mariupol on Monday.
President Volodymyr Zelenskyy said in a video message late Sunday that more than 100 civilians were able to leave Sunday, and that they were due to arrive Monday in Zaporizhzhia, about 200 kilometers away.
Latest Developments in Ukraine: May 2
With Russian troops taking control of the rest of Mariupol, hundreds of civilians and an estimated 2,000 Ukrainian troops have been holed up at the Azovstal steel works. Multiple earlier attempts to evacuate civilians from the site fell apart with Ukraine accusing Russia of shelling evacuation routes.
"For the first time, there were two days of real cease-fire on this territory," Zelenskyy said.
Ukraine's Deputy Prime Minister Iryna Vereshchuk called the situation at Azovstal "a real humanitarian catastrophe" with people running low on food, water and medicine.
The United Nations and the International Committee of the Red Cross conducted Sunday's evacuations, calling it a "safe passage operation."
As many as 100,000 other Ukrainian civilians may still be in Mariupol, located on the northern coast of the Sea of Azov, after a two-month bombing campaign that has all but leveled it.
U.S. House Speaker Nancy Pelosi, who along with six other Democratic lawmakers made an unannounced visit Saturday to Kyiv to meet with Zelenskyy, held talks Monday in Poland with President Andrzej Duda as she pledges support for NATO allies in their efforts to bolster Ukraine.
"Our meetings will be focused on further strengthening our partnership, offering our gratitude for Poland's humanitarian leadership, and discussing how we can further work together to support Ukraine," Pelosi said in a statement Sunday.
Duda said at the start of their meeting that they would discuss "the situation in Ukraine, how to help them, what kind of support they need." He added that this is a "crucial" and "very difficult moment."
About 5.5 million refugees have left Ukraine since Russia invaded the country in late February, according to the United Nations, with more than 3 million of them going to Poland.
Romania has taken in the second most with more than 800,000.
The White House announced Monday that first lady Jill Biden will begin a trip Thursday to Romania and Slovakia that will include meeting with Ukrainians displaced by Russia's invasion. Biden will also meet with aid workers, local families supporting Ukrainian refugees and educators who are helping Ukrainian children continue schooling.
Pelosi was the highest-ranking U.S. official to visit Ukraine since the February 24 Russian invasion that has killed thousands of fighters on both sides and thousands of Ukrainian civilians.
Speaking from Poland after leaving Kyiv, Pelosi said she had vowed to Zelenskyy, "We are with you until this fight is won."
She said the congressional delegation brought him "message of appreciation from the American people for his leadership" in fighting back against the Russian invasion. Pelosi has promised quick House passage of the new $33 billion aid request for Ukraine U.S. President Joe Biden sent to Congress last week.
Republican Congressman Michael McCaul, the lead Republican on the House Foreign Affairs Committee, told ABC's "This Week" show that he too expects Congress to approve the new arms and humanitarian aid package, more than double the $13.6 billion in assistance Congress had already approved.
After early predictions by some military analysts that Russia would quickly overrun Ukraine and topple Zelenskyy, McCaul said he now believes Ukraine "can win it. That should be the goal."
"I think the fighting spirit of the Ukrainians is far superior to that of the Russians," McCaul said.
Oksana Markarova, the Ukrainian ambassador to the United States, told ABC, "None of (the Russians') objectives are met. They are trying to scare Ukrainians. We have to win and we will." She described Pelosi's visit to Kyiv as "yet another sign of the very strong support from the United States."
Britain's defense ministry said more than one-fourth of the 120 battalion tactical groups Russia committed at the start of the conflict in Ukraine have likely "been rendered combat ineffective." The ministry added that some of the most elite Russian units "have suffered the highest levels of attrition."
The Associated Press, Agence France-Press and Reuters provided some information in this report.