Duterte was arrested after arriving from Hong Kong and police took him into custody on orders of the ICC, which has been investigating the massive killings that happened under the former president’s deadly crackdown against illegal drugs, current President Ferdinand Marcos’ office said in a statement.

The ICC launched an investigation into drug killings under Duterte from November 1, 2011, when he was still mayor of the southern city of Davao, to March 16, 2019, as possible crimes against humanity.

During his time in office, Duterte presided over a sweeping and brutal anti-drugs crackdown that killed more than 6000 people, according to police data, though independent monitors believe the number of extrajudicial killings could be much higher.

Duterte withdrew the Philippines in 2019 from the Rome Statute in a move human rights activists say was aimed at escaping accountability over the killings.

The Duterte administration moved to suspend the global court’s investigation in late 2021 by arguing that Philippine authorities were already looking into the same allegations, arguing the ICC — a court of last resort — didn’t have jurisdiction.

Appeals judges at the ICC ruled in July 2023 that the investigation could resume and rejected the Duterte administration’s objections.

Based in The Hague, the Netherlands, the ICC can step in when countries are unwilling or unable to prosecute suspects in the most heinous international crimes, including genocide, war crimes and crimes against humanity.

President Ferdinand Marcos Jr, who succeeded Duterte in 2022 and became entangled in a bitter political dispute with the former president, has decided not to rejoin the global court.

But the Marcos administration has said it would cooperate if the ICC asks international police to take Duterte into custody through a so-called Red Notice, a request for law enforcement agencies worldwide to locate and temporarily arrest a crime suspect.

“Earlier this morning, INTERPOL Manila received the official copy of the arrest warrant from the International Criminal Court (ICC),” according to a statement from the Presidential Communications Office.

Duterte returned to the Philippine capital Manila on Tuesday from Hong Kong after delivering a fiery speech to the city’s Filipino diaspora at a campaign rally on Sunday.

“Upon his arrival, the Prosecutor General filed an ICC notification for an arrest warrant against the former President for crimes against humanity,” the statement said, adding that the former president is currently in the custody of authorities.

During the event in Hong Kong, Duterte lashed out at the ICC investigation amid speculation the global body would issue a warrant for his arrest over his role in his controversial war on drugs operations.