Jihadis are still battling three months after launching an armed offensive on the southern city.
A new report details the close links between ISIS's leadership and the militants who overran Marawi in May.
The controversial leader has repeatedly referenced raping women despite widespread condemnation.
The jihadi group abducted the Vietnamese sailors last year off the southern Philippine coast.
Elected a year ago, one of Philippine president's campaign pledges was to rid the country of "sons of bitches" drug users and dealers.
One year after becoming president, Duterte has managed to insult many international figures.
"He signs papers, he reads, he consults, he's actually very busy."
Images show planes that can detect heat waves, drones, and submarine periscopes being deployed in the South China Sea.
Farhana Maute is the matriarch of the Maute group, currently waging war against the army in Marawi City, Philippines.
Several Singaporeans have been arrested in recent weeks for trying to reach ISIS in Syria and Iraq.
The conflict in the southern Philippines has been raging for more than a month, despite President Duterte's assurances it would be over in three days.
"The school area is again safe."
Duterte had previously warned the international community from "meddling" in the Philippines' affairs.
They fear that new groups will join the conflict after Eid al-Fitr.
The Maute Group and other rebels are targeting Christians in the fight to takeover the city.
There are fears the war across the border in the Philippines will kickstart a flood of militants across the border.
China's relationship with South China Sea neighbors is often contentious.
The war has lasted for 14 days in the southern island of Mindanao.
"I can end this war in 24 hours. All I have to do is to bomb the whole place," Philippines President Rodrigo Duterte said.
The attack by Islamist militants on Marawi had "all the hallmarks of a professional military operation."
ISIS claimed responsibility for the shooting via its Amaq news agency.
Philippine authorities say there's no evidence of terrorism in the attack which left 36 dead and dozens wounded.
Earlier, President Donald Trump said Washington was closely monitoring what he described as a "terrorist" attack unfolding in Manila.
Dozens of people are reported injured after an attack at a resort in Manila.