Russia's Ministry of Defense on Sunday threatened the "elimination" of resistance soldiers still fighting in the besieged southwestern Ukraine city of Mariupol as it confirmed that an ultimatum demanding their surrender had been ignored.

In a statement, it said that Ukrainian soldiers surrounded in a gigantic steelworks in the city had been urged “to voluntarily lay down arms and surrender in order to save their lives.”

“However, the Kiev nationalist regime, according to the radio intercept, forbade negotiations about surrendering,” the ministry claimed.

The ministry also asserted that according to Ukrainian soldiers who had previously surrendered “there are up to 400 foreign mercenaries who joined the Ukrainian forces” trapped at the steel plant, including, it said, Europeans and Canadians.

“In case of further resistance, all of them will be eliminated,” it said.

The Defense Ministry claimed that dozens of military facilities in eastern Ukraine had been destroyed in the latest Russian attacks. These included fuel and ammunition depots, the ministry said, around Severodonetsk, Kremmina and other towns in Luhansk and Donetsk regions.

It also claimed that the Russian air defence system had shot down 10 Ukrainian unmanned aerial vehicles in the Donbas region.