A mayor in the southern Philippines and nine members of his entourage were killed early Friday morning after a clash broke out when anti-drug state operatives flagged down his convoy, according to officials.

The Rappler news website cited police reports as saying that the convoy of Samsudin Dimaukom, mayor of Datu Saudi Ampatuan town in Muslim-majority Maguindanao province, was stopped at a checkpoint in neighbouring Cotabato province “based on information that the group will transport illegal drugs”.

Dimaukom had been among the officials included on a list of alleged drug suspects released by President Rodrigo Duterte in August.

Under a campaign against illegal drugs launched by Duterte, more than 4,440 people have been killed in police operations and “vigilante-style killings” since July 1, according to national police data cited by Rappler.

Maj. Jovit Culaway, chief of the anti-illegal drug unit of the southern Mindanao region, said Friday that when the lead car in the convoy – in which Dimaukom was seated – was slowed down, his security opened the door and opened fire.

Rappler also quoted unnamed sources from Maguindanao as saying said that Duterte had called for the surrender of Dimaukom, who had already been stripped of his police and military escorts by the local government.

More than 700,000 people have surrendered since Duterte’s inauguration June 30, including the mayor of Albuera town in the central province of Leyte, who the president ordered to turn himself in to police or be “shot on sight” in August.

•Text courtesy of Anadolu Agency. Photo shows Philippines President Rodrigo Duterte.