Aside from snipers, the Maute group is now using land mines to stave off the advance of government troops in Marawi City.
Two Marines who were dismantling a land mine in Marawi were killed Sunday after Maute terrorists shot at them, setting off the mine. The two, both members of the Marines 5th Battalion, were killed by shrapnel and gunfire.
Another soldier was killed while 5 other elements of the Army's 51st Infantry Brigade were wounded during a separate encounter.
One of the wounded told ABS-CBN they were establishing their positions in one of the buildings when snipers from different directions opened fire.
"Kabilaan sniper. Dalawang platoon pumasok, pinipilit naming pumasok sa bahay. Sa first floor mahirapan kami makapasok, tina-target na kami," he said.
"Nakapasok yun iba, dahan dahan, pero niraratrat kami galing taas na. Ang kalaban meron sa ground floor, first floor, third floor. Nung napasok namin, may KIA (killed in action) na sa amin isa. Ginapang namin," he added.
The military earlier said up to 200 fighters, most of them from local insurgent groups that have pledged allegiance to Islamic State but also some foreign fighters, are holding out in Marawi, using civilians as human shields and mosques as safe havens.
The attempt by hundreds of well-armed militants to overrun and seal off the city has alarmed governments across Southeast Asia, which fear that Islamic State - losing ground in Iraq and Syria - is trying to establish a foothold in their region that could bring a rash of extremist violence.
More than 300 people have been killed in the battle for Marawi, according to official estimates, including 225 militants, 59 soldiers and 26 civilians. With Reuters