MANILA (Reuters) - Philippine law enforcement agencies still have no proof yet on allegations made by two government officials that human rights groups may have become the “unwitting tools” of drug lords, police and drug enforcement agency officials said on Tuesday.

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 ferocious war on drugs, in which thousands of people have been killed, either by police or by shadowy, unidentified masked gunmen on motorcycles.

The mercurial leader, who says he must be tough to protect the people from the scourge of drugs, has criticised rights groups by saying they were “trivialising” his campaign and unjustly blaming the authorities for bloodshed.

“We have no (proof) right now,” national police spokesman Chief Superintendent John Bulalacao told reporters when asked about proof of links between drug syndicates and human rights groups.

“We are still validating reports that drug syndicates might be using human right groups to discredit the efforts of the government,” he said.

Philippine Drug Enforcement Agency spokesman Derrick Carreon said the reports that drug lords were using rights groups to attack the government’s anti-drug efforts were based on recent findings that would have to be investigated.

“We still have to dig further on this,” he told a regular news briefing at the presidential palace. Carreon said more than 123,000 drug suspects had been arrested since July 2016, which he said showed anti-drugs operations were not about killings.

He said law enforcement agencies welcomed any criticism from rights groups and allowed them to observe anti-drug operations to prove that everything was done according to the rule of law.

“We have made adjustments on the ground in order that we would not be criticised negatively in the conduct of our anti-drugs operations,” Carreon said.

Duterte’s spokesman and foreign secretary did not present any evidence when they told reporters drug lords were using human rights groups to undermine the policy, statements against which the Human Rights Watch protested and said were “shameful” and risked provoking violence.

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 nearly 4,200 drug suspects who were violently resisting arrest since the launch of the crackdown 20 months ago, which Duterte has vowed to pursue until he steps down in June 2022.