MANILA (Reuters) - Some rights groups may have become “unwitting tools” of drug lords in the Philippines to undermine the president, his spokesman said on Monday, a statement that Human Rights Watch said was “shameful” and risked provoking violence.

Philippine President Rodrigo Duterte gestures as he delivers a speech during the 121st founding anniversary of the Philippine Army (PA) at Taguig city, Metro Manila, Philippines March 20, 2018. REUTERS/Romeo Ranoco

Rights groups have denounced President Rodrigo Duterte’s bloody war on drugs in which thousands of people have been killed, either by police or by shadowy, unidentified gunmen.

Duterte, who says he must be tough to protect the people from the scourge of drugs, has criticized rights groups saying they were “trivializing” his campaign and unjustly blaming the authorities for bloodshed.

Drug lords have suffered huge financial losses since the campaign was unleashed 20 months ago and drug syndicates were trying to destabilize the government, the president’s spokesman, Harry Roque, said in a statement.

“We therefore do not discount the possibility that some human rights groups have become unwitting tools of drug lords to hinder the strides made,” Roque said, without naming any rights group.

Roque said attacks on the president’s war on drugs had been “vicious and non-stop”, echoing comments by Foreign Secretary Alan Peter Cayetano last week after he defended the policy at a U.N. human rights council meeting in Geneva.

Roque did not offer any evidence to support the suggestion that rights groups were being used by drug lords.

The anti-narcotics campaign has raised international alarm and drawn criticism from some U.N. representatives, including High Commissioner for Human Rights Zeid Ra’ad al-Hussein, who suggested recently that Duterte needed to see a psychiatrist.

Police say they have killed more than 4,200 drug suspects who were violently resisting arrest since the launch of the crackdown, which Duterte has vowed to pursue until he steps down in June 2022.

Several thousand more people have been killed by unidentified gunmen. Police suspect many were victims of gang wars though activists believe vigilantes supporting the government campaign were responsible for many of the killings.

Brad Adams, Asia director of Human Rights Watch, criticized Roque’s statement, and the earlier comment from Cayetano, as “shockingly dangerous and shameful”.

“Are they trying to have death squads target human rights activists?” Adams asked in a statement.

“Cayetano and Roque provide no evidence. They should withdraw their comments immediately.”

Presidential legal counsel Salvador Panelo said the Human Rights Watch’s call for Cayetano and Roque to withdraw their statements was “misplaced”.

Duterte said on March 14 the Philippines would pull out of the International Criminal Court more than a month after court prosecutors opened a preliminary inquiry into his drug war.

Panelo said Duterte felt the ICC had become “a tool of oppression, a tool of harassment”.