"I have just arrived in Ukraine. In Lviv I will discuss with the authorities, the UN and other partners ways to increase our support to people affected and displaced by this senseless war," Grandi tweeted on Wednesday.

Read here Three evacuation corridors announced in Ukraine

About 80 disabled children, some accompanied by their guardians, have arrived in the border town of Przemyśl, Poland, after being transferred from the central Dnipropetrovsk region on Tuesday.

More than 100 people in total arrived in Przemyśl on Tuesday evening on the train, a spokesperson for the local Podkarpackie Voivode region, Michał Mielniczuk, told CNN on Wednesday.