A Libyan militia spokesman says militias from the western city of Misrata are battling Islamic State militants and have seized vital checkpoints after a brief takeover by the IS.

Mohammed Shamia told The Associated Press Tuesday that the Misrata forces captured three areas south of Misrata including Abu Grain. He said warplanes have bombed IS forces withdrawing from their positions.

Shamia said six Misrata militia fighters were killed and 17 injured. Clashes are ongoing, nearly 50 kilometers (31 miles) from Sirte, the IS stronghold in Libya.

The fighting comes two weeks after IS took over the three areas in surprise attacks. It also comes a day after the United States and other world powers said they would supply Libya's internationally recognized government with weapons to counter the Islamic State group.