MANILA - Two Maute brothers and Isnilon Hapilon, leaders of a months-long terrorist rampage in Marawi City, were likely still alive, contrary to earlier reports, the military said Monday.

The 2 men supposedly killed by recent state offensives were not Omar and Abdullah Maute, but possibly their younger siblings, said Armed Forces spokesperson Brig. Gen. Restituto Padilla.

• Brothers who brought death and ruin to Marawi

Omar and Abdullah, Padilla said, were likely still in Marawi, along with Hapilon, the supposed Islamic State emir in Southeast Asia.

"Iyun pong ating mga nakuhang balita noong araw, na maaaring may 1 o 2 sa magkapatid ang nasawi, may indikasyon po na siguro iyung 2 sigurong mas bata -- hindi po si Abdullah at Omar ang maaaring nasawi," Padilla told radio DZMM.

"Itong 2 mas matanda, si Abdullah at si Omar, ay nandiyan pa po. Ganoon din po sa aming paniniwala si Hapilon."

(As to the earlier reports that one or 2 of the brothers were killed, there is indication that these may be the 2 younger Maute siblings -- not Abdullah and Omar. The 2 older brothers, Abdullah and Omar are still there. We believe the same thing of Hapilon.)

President Rodrigo Duterte previously offered a P10 million reward for the "neutralization" of Hapilon and P5 million each for the Maute brothers.

Thousands of state troops are struggling to quell the siege that the 3 terror leaders launched on May 23, which prompted Duterte to place Mindanao under martial rule.

Security troops have confined the fighting down to only less than a square kilometer within Marawi after sustained close combat and artillery operations.

• READ: More intense firefights as Marawi siege nears end: Año

However, at least 6 suspected bombs on Sunday hit 2 villages in Marantao, Lanao del Sur -- an area outside the battle zone. No one was reported injured in the blasts, but the bombs caused panic in some areas.

The Joint Task Force Marawi has claimed the bombs came from the terrorists, but Padilla said they were still investigating the explosives' source.

The Army spokesperson said the bombs may have been fired by a military unit, planted by terrorists or left in the area long before their explosion.

"Ang atin pong pinaghihinalaan, baka may naging wayward na ordnance na nanggaling sa ating ibang artillery pieces diyan sa ibang lugar. Hindi pa po ito nababatid at inaalam pa natin," Padilla said.

"Tinutukoy natin kung saka-sakaling baka may nakapasok at nakapagtanim or may mga dati nang naiwan diyan na hindi pumutok at naabutan ng pagkakataon na pumutok nitong mga nakaraang araw."

The battle for Marawi, which entered its 77th day on Monday, has left dead at least 690 individuals, Padilla said.

• MORE STORIES: Battle for Marawi