Philippine President Rodrigo Duterte on Monday ordered police in his country that it is OK to kill "idiots" who violently resist arrest, just two days after hundreds turned a funeral of a slain teenager into a protest against his deadly war on drugs.

Duterte made the comments during a speech in a cemetery on the outskirts of Manila. He was addressing a police chief in a town in the southern part of the country where the mayor was killed in an anti-drugs raid, according to Reuters.

“Your duty requires you to overcome the resistance of the person you are arresting... (if) he resists, and it is a violent one... you are free to kill the idiots, that is my order to you,” Duterte told Chief Jovie Espenido.

Police officers watch as protesters and supporters march with the hearse of carrying the body of Kian Loyd delos Santos, a 17-year-old student, during his funeral Saturday, Aug.26, 2017, in suburban Caloocan city north of Manila, Philippines. Murder complaints were filed Friday against Philippine police officers in connection with the killing of a teenager that has sparked an outcry against the president's anti-drug crackdown, which has left thousands dead. (AP Photo/Bullit Marquez)

He added that “murder and homicide and unlawful killings” were forbidden and that the police is obligated to uphold the rule of law.

Later in the day, Duterte met the parents of the schoolboy, 17-year-old Kian Loyd delos Santos, at the presidential palace in Manila, officials said.

Details of the meeting were not immediately available.

The killing of delos Santos by anti-drugs officers on Aug. 16 has sparked rare public outrage since Duterte has unleashed his anti-drugs war when he took office last June. Thousands have been killed as the international community has criticized much of the violence.

Over a 1,000 people – which included nuns, priests and hundreds of children -- joined the funeral procession on Saturday, turning it into one of the biggest protests yet against Duterte’s anti-drugs campaign.

Delos Santos was dragged by plain-clothes policemen to a dark alley in a northern Manila neighborhood before he was shot in the head and left next to a pig pen, according to witnesses. CCTV footage from the scene appears to support their accounts.

Police say they acted in self-defense and Duterte's spokesman and the justice minister have described the killing as an "isolated" case.