THE HAGUE, Netherlands (AP) — Judges at the International Criminal Court on Thursday confirmed crimes against humanity charges against former Philippine president Rodrigo Duterte for deadly anti-drugs crackdowns he allegedly oversaw while in office.

A three-judge panel found unanimously there were "substantial grounds" to believe the ex-leader was responsible for dozens of murders, first as mayor of the southern Philippine city of Davao and later when he was president.

Duterte, who served as president from 2016 to 2022, was arrested in the Philippines last year and flown to the Hague, where the global court is located. He denies the charges against him.

In their 50-page decision, judges found that the evidence shows that Duterte, 81, "developed, disseminated and implemented" a policy "to 'neutralize' alleged criminals."

READ MORE: International Criminal Court opens hearings into Rodrigo Duterte

According to prosecutors, police and hit squad members carried out dozens of murders at Duterte's behest starting in 2011, motivated by the promise of money or to avoid becoming targets themselves.

"For some, killing reached the level of a perverse form of competition," deputy prosecutor Mame Mandiaye Niang told the court in pretrial hearings in February.

Estimates of the death toll during Duterte's presidential term vary, from the more than 6,000 that the national police have reported to up to 30,000 claimed by human rights groups.

Prosecutors said in a statement on Wednesday that the decision "represents a significant milestone" in their effort to bring accountability.

Duterte's lead defense lawyer Nick Kaufman told The Associated Press he was disappointed in the decision, saying it "is based on the uncorroborated statements of vicious self-confessed murderers acting as cooperating witnesses."

A date for the start of the trial has not yet been set.

Duterte has not been present in the courtroom for any hearings, having waived his right to appear. Last month judges found he was fit to stand trial, after postponing an earlier hearing over concerns about his health.

In the Philippines, families of slain victims in the brutal anti-drugs crackdown rejoiced over the decision, saying it will bring them closer to justice and toward a closure of a tragic chapter in their lives.

"This is for all the victims, who were not even given the chance to be recognized as victims because their stories were twisted in police reports, investigations and findings," said Randy delos Santos, whose nephew, Kian delos Santos, was gunned down in an alley in August 2017 by three police officers.

"Unlike Kian, most other victims were nameless, voiceless and were just numbers and statistics whose horrific stories were never heard. Now the ICC will give their stories a chance to be told," delos Santos told The Associated Press.

Human rights groups also praised the decision.

"Duterte's trial will send a powerful message that no one responsible for grave crimes is above the law, whether in the Philippines or elsewhere, and that justice will eventually catch up with them," Maria Elena Vignoli, senior international justice counsel at Human Rights Watch, said.

ICC prosecutors said in 2018 that they would open a preliminary investigation into the violent drug crackdowns. In a move that human rights activists say was aimed at avoiding accountability, Duterte, who was president at the time, announced a month later that the Philippines would leave the court.

READ MORE: What happened during Duterte's chaotic arrest

On Tuesday, appeals judges rejected a request from Duterte's legal team to throw out the case on the grounds that the court did not have jurisdiction because of the Philippine withdrawal.

In October, judges disqualified the court's chief prosecutor Karim Khan from the case, citing a "reasonable appearance of bias" because he represented victims of Duterte's alleged crimes before he took office at the ICC. Khan had already stepped back from his duties pending the outcome of an independent investigation into allegations of sexual misconduct.

Associated Press journalist Jim Gomez in Manila, Philippines contributed to this report.