Fresh attempts to evacuate civilians from cities under siege in Ukraine are being complicated by constant Russian shelling, Ukrainian officials say.
Humanitarian corridors are being set up from Mariupol, Sumy and towns and villages outside the capital Kyiv.
The situation in Mariupol is particularly desperate after two weeks of bombardment, the UN says, with little access to food, water and power.
The evacuations come as fighting continues around Kyiv.
The BBC's Abdujalil Abdurasulov in Irpin, one of the towns outside the capital being evacuated, says it is not possible to say that the humanitarian ceasefire is holding because explosions and artillery fire, including from the Ukrainian side, can still be heard.
Regional officials also said that fighting in the area was continuing and that there was a constant threat of air attacks.
Mariupol Deputy Mayor Serhiy Orlov told the BBC a convoy had left Zaporizhzhya for the city carrying aid and including buses for the evacuations, but it was not clear whether it would get through.
"This is the seventh attempt. On the previous six it didn't work. The convoys were not let through, they were bombed, the road was mined, there was shelling in the town," he said.