Maria Ressa has been a vocal critic of Duterte and the deadly drug war he launched in 2016, triggering what media advocates say is a grinding series of criminal charges, probes and online attacks against her and Rappler.

Candidates hit the hustings for the three-month campaign season in a charm offensive aimed at wooing millions of voters typically more interested in personality than policy.

He says those who have not been vaccinated will be arrested if they disobey stay-at-home orders.

His withdrawal does not necessarily mean he is planning to retire from politics after the elections in May.

The release of details of 50 drug war deaths marked a rare admission by the state that abuses may have taken place.

With their decisions made, the spotlight for the presidency could shift to the controversial son and namesake of the late dictator Ferdinand Marcos.

The Southeast Asian nation of 110 million people holds elections in May 2022 for positions from president down to governors, mayors and local officials.

The Philippines, which has one of Asia's worst coronavirus epidemics, has so far fully immunised a little over a third of 77 million people eligible for shots.

The Philippines has come under pressure from the United Nations to investigate allegations of systematic murders of drug suspects.

Duterte has repeatedly attacked the world's only permanent war crimes court and insisted it has no jurisdiction in the Philippines.

Sara Duterte-Carpio is currently mayor of Davao, the Philippines' third-largest city, and had previously said she would not run for national office next year.

More than 6,100 suspected drug dealers and users have been killed since he took office in June 2016.