Russia threatened to “annihilate” the thousands of Ukrainian troops still fighting for control of the embattled port city of Mariupol on Sunday, after Moscow’s deadline for their surrender elapsed. The units, including 400 foreign mercenaries, are holed up in the Azovstal steelworks, Russian Defence Ministry spokesman Igor Konashenkov said. He said the Ukrainian government had forbidden them to surrender. Moscow had earlier set a deadline of 1000 GMT for the remaining troops to surrender, saying that those who did so would live. Konashenkov said that if the fighters resisted any longer, “they …