The Philippine national police plan to investigate testimony by former President Rodrigo Duterte that he used to keep a "death squad." He said the team killed criminals when he served as mayor of the southern city of Davao until 2016.

Duterte testified on Monday before a Senate investigation into his deadly crackdown on drug crime. The 79-year-old said, "I had a death squad. The squad members were not policemen but gangsters."

Duterte had long denied the group's existence. After serving as mayor, he was elected president, promising to take his anti-crime campaign nationwide.

The government has confirmed that Duterte's so-called "war on drugs" killed over 6,000 people across the country. Human rights groups believe the death toll is far higher.

The Philippine police say they will use the information from the latest congressional hearings to pursue their investigation. The International Criminal Court is also probing the crackdown for possible crimes against humanity.

A lawyer representing the victims who filed the complaint with the ICC, Neri Colmenares, believes Duterte's confession will make the case. He said: "It was major evidence on our part. If there are more admissions, then that would be good. But just the admission of Duterte practically ensures his conviction."

The Philippines has called the court a threat to the country's sovereignty and said it will not cooperate with its inquiry. Manila left the ICC in 2019.