President Rodrigo Duterte said on Thursday the Islamic State of Iraq and Syria (ISIS) is the one behind the attack in Marawi City.

In a speech during the mass oath taking in Malacanang, Duterte said the siege in Marawi City by the terrorists had "long been planned.

"It could not be just a decision that 'let's go to Mindanao.' These were all planned," he said, citing that the founders of the Maute brothers, who founded the Maute Terror Group, went to Libya.

"You know what, the rebellion now in Mindanao. It's not Maute, it's purely ISIS with different branch because they started it," he said.

The Maute brothers also built a huge drug factory in Mindanao to fuel insurrection, he said.

Duterte said he was "very sad" that many government troopers have been killed in fighting the terrorists.

"I'm very sad. I have lots of soldiers killed, lots of policemen killed...I lose about three, four (a day). It keeps on increasing everyday for as long as war rages on," he said.

During the speech, Duterte did not say anything about the death of 11 soldiers who were killed by the government's own bomb supposedly for militants in Marawi on Wednesday.

Duterte said he was one of those who wanted to immediately end the problem so that the declaration of martial law in Mindanao could be lifted.

"The earlier we attain the equanimity of the community, the stability, I'd be the first to clamor for the lifting of martial law," he said.

He also belied allegations he did not consult his security officials when he declared martial law on May 23 while he was in Russia.

"They said I did not consult the military. You can hardly talk to the fools and to the stupid, they will never understand. You do not declare martial law without asking the soldiers and the policemen," he said.

Duterte reiterated that his decision to lift the imposition of martial law in southern Philippines would be based on what the military and the police would tell him.

He said if martial law declaration would go beyond 60 days, "Congress must understand that I may need more time.

"There's Jolo, which is also bursting. And on top of that, I am facing three fronts. I have terrorism in Mindanao; I have the drug problem; and this ordinary, kidnap-for-ransom and everything," he said.

Since he declared war against these problems, he said, "my orders really are to wipe them out, everyone."

"When I say, wipe them out, better. If you shoot him in the head, shoot it again in the heart to be sure (the person is dead)," he said. Celerina Monte/DMS