NDTV reported that Ukrainian President Zelenskyy asked the UN chief Antonio Guterres to help "save" Ukrainians remaining trapped underneath the Azovstal steel plant in the besieged city of Mariupol.

"The lives of the people who remain there are in danger. Everyone is important to us. We ask for your help in saving them," the Ukrainian leader told Guterres in a phone call, asking the UN to "assist in the removal of all the wounded..."

The statement came as Russia announced its troops had entered the plant, which had been under constant attack for weeks.