Philippine President Ferdinand Marcos said Monday he would not hand his predecessor Rodrigo Duterte to the International Criminal Court, which is investigating his deadly drug war.

Thousands of people have been killed in the anti-narcotics campaign started by Duterte in 2016 and continued under Marcos.

Asked Monday if he would hand Duterte -- who has accused him of being a drug addict and criticised his policies -- to the ICC if it issued a warrant for his arrest, Marcos said "no".

"We don't recognise the warrant that they will send to us. That's a no," he said at a forum with the Foreign Correspondents Association of the Philippines.

"We are well within international law when we take the position of not recognising the jurisdiction of the ICC in the Philippines," Marcos said.

Duterte withdrew the Philippines from the ICC in 2019 after the Hague-based tribunal started probing allegations of human rights abuses committed during his drug war.

It launched a formal inquiry into Duterte's crackdown in September 2021, only to suspend it two months later after Manila said it was re-examining several hundred cases of drug operations that led to deaths at the hands of police, hitmen and vigilantes.

The ICC's chief prosecutor later asked to reopen the inquiry, and pre-trial judges at the court eventually gave the green light in late January 2023 -- a decision that Manila appealed shortly afterwards and lost.

More than 6,000 people were killed in anti-drug operations under Duterte, according to official data released by the Philippines. ICC prosecutors estimate the death toll at between 12,000 and 30,000.

- 'It's complicated' -

The drug war has continued under Marcos even though he has pushed for more focus on prevention and rehabilitation.

Marcos has repeatedly ruled out rejoining the ICC and insisted it does not have jurisdiction in the country because there is a functioning judicial system.

Relations between the Marcos and Duterte families have fractured in the past two years.

Marcos, the son and namesake of the country's former dictator, won the 2022 presidential election by a landslide following a massive social media misinformation campaign whitewashing his family's history.

His vice presidential running mate Sara Duterte, the daughter of the former president, helped him win vital support from her family's home island of Mindanao.

In recent months there has been a very public falling out between the families as they begin to shore up their rival support bases and secure key positions ahead of the mid-term elections in 2025 and presidential elections in 2028.

Duterte and Marcos have accused each other of drug abuse, while Duterte previously called for his family's home island of Mindanao to separate from the rest of the country.

Asked to describe his current relationship with the Duterte family, Marcos said "it's complicated", before laughing with the audience.