MANILA — The Philippine military said on Wednesday that troops had found the mutilated bodies of 17 civilians in the besieged southern city of Marawi, where government forces have been struggling to dislodge militants who have entrenched themselves for the last month.

The bodies were recovered Wednesday while troops and police officers conducted clearing operations near Gadungan, a devastated section of the city. The discovery came more than a month after Islamic State-inspired gunmen with the Abu Sayyaf and Maute militant groups overran Marawi, a city of 200,000.

“The recovered cadavers are believed to be among those civilians who were helplessly murdered by the Maute and Abu Sayyaf terrorists,” said Brig. Gen. Rolando Bautista of the Philippine Army. “This is a manifestation of their brutality. They killed these innocent civilians in cold blood.”

The grisly discovery came as government troops were struggling to retake the city from the Islamist militants, whose numbers are believed to have dwindled to between 150 and 200 fighters.