US Secretary of State Antony Blinken and Secretary of Defense Lloyd Austin will travel to Kyiv on Sunday and hold talks with Ukrainian President Volodymyr Zelenskiy, the Ukrainian leader said on Saturday.
He told a news conference in Kyiv that he would discuss the kinds of weapons that Ukraine needs to battle Russia's invasion.
Russia resumed its assault on the last Ukrainian defenders holed up in a giant steel works in Mariupol, a Ukrainian official said on Saturday, days after Moscow declared victory in the southern port city and said its forces did not need to take the factory.
A new attempt to evacuate Ukrainian civilians from Mariupol failed on Saturday, an aide to the city's mayor said, blaming Russian forces. The official said 200 residents of Mariupol had gathered to be evacuated, but that the Russian military told them to disperse and warned of possible shelling.
Zelenskiy said Ukraine's army was not ready to try to break through Russia's siege of Mariupol by force, but that Kyiv had every right to try and do so.
He stressed it was vital that he meet Russian President Vladimir Putin for talks if Ukraine planned to resolve the war through diplomacy.
UN Secretary-General Antonio Guterres will hold talks with Putin, traveling to Moscow on Tuesday. He will then head to Ukraine for talks with Zelenskiy.
Elsewhere, at least five people were killed and 18 injured in a missile strike on Ukraine's southern port city of Odesa, the president's chief of staff Andriy Yermak said in an online post.
Ukraine's southern air command had earlier said that two missiles struck a military facility and two residential buildings in Odesa.