“You can see that [IS] is here already,” Duterte said in a speech yesterday at a military camp near Marawi, as officials said the insurgents were from multiple countries.

Six foreign fighters were believed to have died in the bloodshed, according to Philippine military spokesman Brigadier-General Restituto Padilla, including Malaysians, Indonesians and another nationality which he did not specify. Another government official listed Singaporeans as also among the militants.

Padilla said 11 soldiers, two policemen and 31 militants had been confirmed killed in the fighting, which has involved the military bombing buildings where the militants have been hiding.

Two civilians were killed in a hospital the gunmen occupied on and the military was ­investigating reports nine people were murdered at a checkpoint the militants set up.

The fighting erupted after security forces raided a house where they believed Isnilon Hapilon, a leader of the infamous Abu Sayyaf group and Philippine head of IS, was hiding. The US regards Hapilon as one of the world’s most dangerous terrorists, offering a bounty of US$5 million for his capture.

The raid went wrong as dozens of gunmen emerged to repel security forces, then tore across the city flying black IS flags.

Authorities said ending the crisis was proving extremely hard because the militants, even though they were believed to number only in the dozens, had planted bombs in the streets and were holding hostages.

They said militants had also occupied higher ground in the city, enabling them to slow down or stop assaults from the army.

Snipers fired on Friday afternoon at about 100 troops who were marching single-file uphill through a district the militants had previously controlled, according to journalists.

The troops pulled down a black IS flag that was raised on top of one house as the gunfire from uphill intensified.

Duterte said the militants belonged to the Maute group that has emerged only in recent years in Mindanao and gained strength on the proceeds of drug money.

The group had 263 armed followers at the end of last year, according to Duterte’s report to Congress to justify martial law, which was released to the media yesterday.

Duterte joked on Friday that soldiers could rape up to three women, as he reassured them of his full support under his newly imposed regional martial law.

He made the comments in jest during a speech at a military base to lift the spirits of troops tasked with quelling what he says is a fast-growing threat of Islamist terrorism.

“For this martial law and the consequences of martial law and the ramifications of martial law, I and I alone would be responsible. Just do your work. I will handle the rest,” he said.

“I will be imprisoned for you. If you rape three [women], I will say that I did it.”

The Philippine military said on Friday it would censor the press and social media to protect “national security” across Mindanao and warned violators would be arrested.

“We’ll exercise the right to censure,” Padilla told reporters. In a text message later, he clarified that he had meant “censor”.

At the press conference, Padilla the censorship would be based on three conditions.

“One, to ensure the safety of lives, second to ensure operational security and ensure the safety of our men in uniform who are fighting, and for other national security considerations,” he said, noting that social media in particular would be subject to censorship and warning people against posting material that breached the conditions.

“That’s why we are appealing to you now while there’s still time, to exercise your common sense, he said. “If you know that this will harm the public and will not be helpful, better not post it because police might come to your door later on and arrest you.”

Some critics of Duterte say he might be exaggerating the IS threat to justify a form of authoritarian rule that will give him greater powers to carry out his crackdown on drugs, which has claimed thousands of lives.