President Rodrigo Duterte warned on Friday that his decision to allow the Philippine Drug Enforcement Agency to be the sole and lead agency in war on drugs could result to "more serious" consequences.

In a speech in Dumaguete City, Duterte indicated he was only forced to strip the Philippine National Police of its task in the drug campaign due to strong criticisms from the church and other human rights groups.

"There were lots of noises in deference to everybody. But I do not want to strike fear in your hearts. I have decided to call off drug operations except to one sole agency, the PDEA," he said, noting that he received a message from a bishop through a friend regarding his war on drugs.

"I have gambled it, but all knew it, the military and also the police, the consequences of that could be far more serious," he said.

Duterte earlier issued a memorandum directing the PNP and other concerned agencies to allow the PDEA to be the lead agency in the anti-drug operations.

He said the people know the magnitude of drugs in the country.

But since the public wants PDEA to do the operation in order to pinpoint responsibility, he issued the memorandum.

"But that is fraught with so many grave consequences," Duterte said.

Thousands have been killed in the government's anti-drug operations, particularly being conducted by policemen.

Most of the slain drug suspects were allegedly victims of the summary executions. Celerina Monte/DMS