MANILA, Oct. 16 (Xinhua) -- The Philippine defense chief said on Monday that two top leaders of pro-Islamic State (IS) militant groups that laid siege to the southern Philippine city of Marawi had been killed in action.

Defense Secretary Delfin Lorenzana said Isnilon Hapilon, the alleged emir of the IS jihadist group in Southeast Asia, and Omarkhayam Maute were killed in a firefight. Their bodies were found on Monday in Marawi, he said.

"I think they were killed by the soldiers," Lorenzana said.

Hapilon is among the terror suspects on the FBI list with a 5-million-U.S. dollar county on his head. Omarkhayam Maute is the brother of Maddi Maute, who was reportedly killed earlier in the gun battle. The military said Hapilon and the Maute brothers plotted the Marawi siege on May 23.

Lorenzana said troops also rescued 17 hostages, including an infant and women, at the scene of the battle where Hapilon and Maute were killed.

He said they will announced the "termination" of the Marawi City operation in the couple of days. Hapilon and the Maute brothers led the attack on Marawi on May 23, which had dragged on for nearly five months.