The Philippines deployed attack helicopters and special forces to drive out Islamic State-linked rebels holed up in a besieged southern city on Thursday, as efforts to take back control met heavy resistance.

Ground troops hid behind walls and armoured vehicles and exchanged volleys of gunfire with Maute group fighters, firing into elevated positions occupied by militants who have held Marawi City on Mindanao island for two days.

Machine gun fire

Helicopters circled the city, peppering Maute positions with machine gun fire to try to force them from a bridge vital to retaking Marawi, a mainly Muslim city of 200,000 where fighters had torched and seized a school, a jail, a cathedral, and took more than a dozen hostages. “We’re confronting maybe 30 to 40 remaining from the local terrorist group,” said Jo-Ar Herrera, spokesman for the military's First Infantry Regiment. “The military is conducting precise, surgical operations to flush them out... The situation is very fluid and movements are dynamic because we wanted to out-step and out-manoeuvre them.”

The battles with the Maute group, which has pledged allegiance to IS, started on Tuesday afternoon during a failed raid by security forces on one of the group's hideouts, which spiralled into chaos.

The turmoil was the final straw for President Rodrigo Duterte, who delivered on his threat to impose martial law on Mindanao, the country’s second-largest island, to stop the spread of radical Islam.