Former Philippine President Rodrigo Duterte says he has filed his candidacy for mayor of Davao City in the country's south.

Duterte on Monday revealed on social media that he decided to run for the mayoral post in the largest city on Mindanao island, which is part of the May 2025 midterm elections.

This comes as Duterte's relationship with incumbent President Ferdinand Marcos Jr. has turned confrontational this year. Vice President Sara Duterte, the eldest daughter of the former president, has signaled that her father is ready to build up his political influence through the midterm elections.

The 79-year-old Duterte, however, said last week that he found it difficult to pursue a nationwide election campaign because of his age.

Duterte served as Davao's mayor for more than two decades before becoming president in 2016. He was credited with making the city safer through such measures as giving the police more powers.

As president, he oversaw a massive crackdown on drug crime, which authorities admitted led to the deaths of more than 6,000 people. He had appeared tolerant of extrajudicial killings of drug suspects.

His anti-drug campaign is being investigated by the International Criminal Court as a possible crime against humanity.