"As of now, the Azovstal plant is under intense shelling, and in just one night, we have counted more than 25 sorties, including three strategic bombers," Svyatoslav Palamar, deputy commander of the Azov Battalion said on Sunday, according to the Ukrainian news agency UNIAN.

"We will continue to fight as long as we are alive to repel the Russian occupiers," he added, pleading with the international community to help evacuate wounded soldiers from the plant.

There has been no response yet from Russia.

(With input from Reuters)