MANILA - The British government warned its nationals to avoid traveling to western Mindanao, including Marawi City where clashes are still ongoing between government troops and Maute group terrorists.

"The Foreign and Commonwealth Office (FCO) advice against all travel to western Mindanao and the Sulu archipelago because of terror activity and clashes between the military and insurgent groups," the United Kingdom said in its website.

"The FCO advice against all but essential travel to the remainder of Mindanao and to the south of Cebu province, up to and including the municipalities of Dalaguete and Badian, due to the threat of terrorism," it added.

The fighting began when police and troops raided a house on Tuesday afternoon where Isnilon Hapilon, the subject of a US State Department bounty of $5 million, was believed to be hiding.

The Maute group torched several establishments including schools, a church, and the city jail.

• LOOK: Marawi City jail, Dansalan College on fire

"If you’re in the affected area you should remain indoors, monitor media reporting and follow the advice of the Philippine authorities," the advisory added.

It likewise urged its nationals to remain vigilant and to report anything suspicious to local authorities.

President Rodrigo Duterte cut short his Russian visit to return home after declaring martial law in Mindanao.