TRIPOLI (Reuters) - Forces aligned with Libya's unity government said they had made significant gains in residential districts of Sirte on Tuesday as they battle to oust Islamic State from its coastal stronghold.

Rida Issa, a spokesman for the government-backed brigades, said they were securing the "700" neighborhood just south of central Sirte, and had also made ground to the west of the city center. Sixteen brigade members had been killed and 60 wounded in Tuesday's fighting, Issa said.

(Reporting by Ahmed Elumami; Writing by Aidan Lewis; Editing by Hugh Lawson)