This was confirmed by Defence Secretary Delfin Lorenzana, the Philippine Daily Inquirer reported.

Citing sources, Philippines news site Rappler said Omar and Hapilon, who is wanted by Esscom for transborder crimes in Sabah’s east coast waters, were killed as troops attacked the enemy to rescue hostages.

AP meanwhile reported that according to four military and police officials, Hapilon, who is among the FBI’s most-wanted terror suspects, and Omar were killed in a gun battle and their bodies found on Monday in Marawi.

The military is expected to continue operations to clear the militants’ last battle area and their improvised explosive devices, Rappler said.

“We have heard news that Isnilon has been killed and we are waiting for confirmation from our Philippine counterpart,” Esscom chief Hazani Ghazali told FMT.

“We are tightening operations to secure our borders in the east coast with southern Philippines to ensure no remnants of militants enter our waters.”

Militants were reported to have surrendered after their sub-commanders were killed, sparking fears that they would flee to other areas in southern Philippines or even to Indonesia and Malaysia.

A photo of a bloodied Hapilon, his face raised for the camera by a soldier, has reportedly been circulating among Marawi residents.

The photo shows him wearing a black jacket over a black shirt, the colour that the armed groups have worn since the fighting broke out.

Hapilon is the leader of the Abu Sayyaf militant group and emir-designate of the so-called IS for Southeast Asia.

Omar is the co-founder of the Maute militant group. His brother, Abdullah, the other co-founder, was reported to have been killed during fighting.

More than 1,000 people, mostly militants, have been killed during clashes between both terror groups and troops which erupted on May 23.