The International Criminal Court issued an arrest warrant for a Philippine senator linked to the deadly drug war overseen by ex-president Rodrigo Duterte.

The warrant charges Ronald dela Rosa with the crime of murder of at least 32 people between 2016 and 2018.

Duterte and dela Rosa denied authorizing killings, but Duterte threatened drug suspects with death. They said suspects were shot after threatening law enforcers.

Philippines' ex-president is arrested for 'war on drugs' killings.

The warrant says dela Rosa contributed to the crime of murder and is an 'indirect co-perpetrator'.

Dela Rosa appeared in the Senate after being summoned for an investigation. He sought protection from fellow senators.

A former senator showed the warrant to the media, and the ICC confirmed it.

Dela Rosa was the national police chief under Duterte and enforced the campaign against illegal drugs.

Philippine police summoned dela Rosa for an investigation into his role in the killings.

A Human Rights Watch counsel welcomed the warrant, calling it a blow to impunity.

She called on Philippine authorities to detain dela Rosa and send him to the court.

Duterte was arrested last year and detained in the Netherlands on charges of crimes against humanity.

He denies the charges, but judges ruled there is enough evidence for a trial. No date has been set.

The killings of drug suspects took place when Duterte was mayor and president, alarming human rights groups.