Police in The Philippines have arrested former President Rodrigo Duterte on an International Criminal Court (ICC) warrant linked to an investigation into his highly controversial "war on drugs" in which many thousands were killed.

Duterte was detained at  Ninoy Aquino International Airport in Manila shortly after arriving back in the country from a trip to Hong Kong according to sources in the city.

Local media, Inquirer.net, later said “Duterte is now at Camp Crame in Quezon City” to the Northeast of central Manila. He has been checked by medical professionals and in understood to be in good health for his age.

It is believed the nation’s Prosecutor General, Richard Anthony Fadullon served the “ICC notification for an arrest warrant against the former president.”

The 79-year-old led is infamous across the Philippines and much of East Asia for his brutal anti-drugs campaign during a presidency that ran from 2016 to 2022. It is believed over 12,000 people were killed as part of the campaign – many in extra-judicial and gang-related killings at the hands of death squads. Some put the number as high as 20,000.

There have long been claims that the death squads acted on orders issued from political elites.

Duterte had previously stated he was prepared to go to prison in response to reports of his potential arrest multiple sources say. Prior to returning to the country, he attended an event in Hong Kong where it is believed he criticised the ICC investigation into his actions as president.

If ultimately delivered to the ICC in The Hague and prosecuted, he will face the charge of crimes against humanity.