Russia on Tuesday called on Ukrainian forces and foreign mercenaries to leave the Azovstal metallurgical plant in the besieged Ukrainian city of Mariupol by noon Moscow time (0900 GMT).

"All who lay down their arms are guaranteed to remain alive," the defence ministry said.

Earlier on Tuesday Russia-backed separatist forces said they were trying to storm the Azovstal metallurgical plant, the RIA news agency quoted separatist spokesperson Eduard Basurin as saying.

(Reporting by Reuters)