(Reuters) - About 120 civilians living next to the Azovstal steel works in the besieged Ukrainian port of Mariupol have left via humanitarian corridors, the Interfax news agency reported on Tuesday, quoting Russian state TV.

       Interfax said a TV correspondent quoted the Russian-backed separatist administration of Donetsk in eastern Ukraine as saying, however, that no Ukrainian fighters had accepted a Russian ultimatum to surrender their arms and leave the factory on Tuesday afternoon in return for a promise to spare their lives.

       Ukrainian fighters holed up in the vast steel plant have been mounting a last stand in the ruins of Mariupol, which Russian forces have been attacking almost since the start of what Moscow calls its special military operation in Ukraine.

       (Reporting by Reuters; editing by Jonathan Oatis)