Duterte says he had to declare martial law to fight ISIS in Mindanao

"I had to declare martial law in the Mindanao group of islands," Duterte said at a news conference Wednesday. "It is our constitutional duty to enforce the law and provide security."

Duterte's order -- which covers both the city of Marawi and the wider island of Mindanao, of which Marawi is a part -- came after deadly clashes broke out between Filipino government troops and Islamist militants Tuesday.

If the terror threat spreads, Duterte said he's not afraid to go further.

Welcome to Duterte country

He was born and raised here. He served as the local mayor for seven terms. Even now, as President, he flies back and forth to Davao City, saying he prefers his own bed to sleeping in Manila's Malacanang Palace, the traditional home of Philippine leaders.

The President has captured the world's attention with his combative and at times vulgar comments. He told the EU they could f**k themselves and called US President Barack Obama a "son of a bitch."