The Ukrainian army continues to defend in besieged Mariupol, destroyed by Russian shelling, but the situation on Azovstal is desperate, the Ukrainian Foreign Ministry has said.

"Hundreds of civilians, children, injured Ukrainian defenders are trapped in plant's shelters. They have almost no food, water, essential medicine. An urgent humanitarian corridor is needed from the Azovstal plant with guarantees people will be safe," the Ukrainian Foreign Ministry said on Twitter.

"Russia is responsible for its war crimes. Its authorities know they kill civilians. Russia ruined Mariupol. The invaders killed and tortured thousands of civilians. They act as terrorists. Russia must stop its war crimes, face consequences, tightened sanctions, further isolation," the ministry said.