MANILA- A 15-year-old boy became the latest victim of the ongoing siege in Marawi City, where government troops and Islamic State-linked terrorists have been engaged in firefights for over two weeks now.

The boy, who was doing noontime prayers, was killed by sniper fire inside a mosque in the battle-torn city.

He was a sixth grader at the Datu Saber Elementary School in the city.

Clashes between government troops and Maute and Abu Sayyaf group terrorists broke out on May 23, as state forces attempted to arrest terror leader Isnilon Hapilon, known to be the anointed ISIS chief in Southeast Asia.

Video found by the military showed that Hapilon and other terror leaders planned to carry out attacks in the city days before the clashes began.

The firefights prompted President Rodrigo Duterte to declare martial law over the entire island of Mindanao while state forces scrambled to bring back a sense of normalcy to the Islamic city.

The military said it hoped to liberate the city on June 12, Independence Day.

More than 200 have died in the firefights, among them at least 30 civilians. More than 200,000 residents have also fled the city since clashes began. --report from Chiara Zambrano, ABS-CBN News