MANILA (Reuters) - The Philippines’ police chief stepped down on Monday less than a month before his retirement, after he was accused of involvement in “recycling” confiscated drugs, an allegation that could undermine the government’s anti-narcotics campaign.

FILE PHOTO: Incoming Philippine National Police Chief Oscar Albayalde arrives for the National Police chief handover ceremony in Camp Crame, Quezon City, metro Manila, Philippines, April 19, 2018. REUTERS/Dondi Tawatao/File Photo

President Rodrigo Duterte has made a bloody war on drugs his signature campaign, to the approval of most voters, despite international outrage about the bloodshed amid fears many suspected dealers have been killed by police in staged encounters and by death squads.

Duterte has rejected the accusations.

In testimony that has raised questions about the government’s campaign, witnesses in Senate inquiries have accused police chief Oscar Albayalde of protecting officers who sold confiscated narcotics back onto the black market.

Albayalde denied the accusations and had ruled out resigning.

On Monday, he referred to the hearing and the fact he was being implicated in the scandal and said he was stepping down to make way for a new police chief.

“After careful thought and deliberation, I have come to the decision to relinquish my post as chief of the Philippine National Police,” Albayalde said in the speech to police officers.

Albayalde, the second chief of the 191,000-strong force under Duterte, was the head of the Pampanga provincial police when 13 of its officers were accused of stealing about 160 kg (353 lb) of narcotics seized in a 2013 raid.

Albayalde had sought to prevent the dismissal of the 13, Senate witnesses said.

Presidential spokesman Salvador Panelo told ANC news channel that perhaps Albayalde was stepping down because he had had enough of the “the accusations, the innuendos”.

“He wants to spare the entire organization from whatever speculations, bad or false about him and the organization,” Panelo said.

Albayalde was set to retire on Nov. 8.

The police are spearheading the anti-drugs campaign. They say they have killed more than 6,700 suspected drug dealers who resisted arrest, and deny involvement in the mysterious killing of thousands more suspected drug users.

But Duterte has at times criticized the force, once deriding it as “rotten to the core” and twice suspending anti-narcotics operations until the police cleaned up the force.

The thousands of killings, mostly of poor urban people, have alarmed rights groups. The 47-member U.N. Human Rights Council in July approved a resolution to investigate the crackdown.

Duterte condemned the proposed investigation.