Philippine President Rodrigo Duterte declared martial law on the southern island of Mindanao Tuesday. Duterte, who was on a trip to Russia to meet with Vladimir Putin, will cut his trip short and return home. Duterte’s action was prompted by a chaotic battle between Philippine security forces and a group linked to ISIS. From the Associated Press:

Defense Secretary Delfin Lorenzana said troops raided the hideout of a top terrorist suspect in southern Marawi city on Tuesday, sparking a gunbattle that prompted the militants to call for reinforcements from an allied group, the Maute. He said dozens of gunmen occupied city hall, a hospital and a jail and burned a Catholic church, a jail, a college and some houses in a bold attack that killed at least two soldiers and a police officer and wounded 12 others.

Several militants were killed in the fighting in Marawi city in Lanao del Sur province, about 830 kilometers (520 miles) south of Manila, but others continued to lay siege to the largely Muslim city of more than 200,000 people, officials said, adding that power was cut in the city in a chaotic scene.

“The whole of Marawi city is blacked out, there is no light, and there are Maute snipers all around,” Lorenzana said in the news conference in Moscow, which was broadcast live in the Philippines.

Duterte has been sharply criticized for his ruthless approach to fighting drug dealers in the country. From the Guardian:

After more than 20 years as mayor of Davao, Duterte won the presidential election last May with promises to rid the country of drugs and crime, to kill every drug dealer and user, and to feed their corpses to the fish in Manila Bay…

The death toll of the president’s drug war in the nine months since he took office at the end of June has topped more than 2,500 killings by police and 3,600 by vigilantes. Agencies including Amnesty quote a total figure of more than 7,000 dead. But many Filipinos gloss over the killings and Duterte’s poll ratings remain high.

Given that track record, there is concern Duterte will not tread lightly given the additional powers of martial law. He had previously warned on several occasions that he might declare martial law in order to deal with the drug trade and the threat of terrorism. But as the Washington Post points out, people in the Philippines still remember the last time a President declared martial law: “In 1972, then-President Ferdinand Marcos declared martial law to ensure that he would remain in power beyond the end of his second term the following year.” Marcos ruled for 14 additional years and was finally overthrown in 1986.