He said Duterte's memorandum order was "in response to a clamour from the public to restore to the PNP and other law enforcement agencies the responsibility of providing active support to the PDEA".
The PDEA said it had received reports that some drug pushers chose to be billeted inside hotels to conduct their illegal trade because they believed that no law enforcement authorities would try to arrest them in these establishments where a ban on carrying firearms is strictly being enforced.
Efforts by a Philippine agency to combat drug trafficking will be supported by the country's law enforcement officers, in a sign that the government is seeking to reinforce its anti-drug campaign.
The Dangerous Drugs Board shall remain as the policymaking and strategy-formulating body in the planning and formulation of policies and programmes on drug prevention and control.
After a growing sentiment of opposition pushback against Duterte's anti-drug campaign and facing accusations of police abuse, the president chose to shift his policy and made the announcement on 12 October that the PDEA would be taking the reins from the PNP.
However, he said PDEA has been seriously hampered in performing its huge mandate by lack of resources, specifically agents and operatives who can penetrate drug-infected areas down to the municipal and village levels.
Philippine police on Tuesday were ordered to rejoin the war on drugs, overturning President Duterte's decision two months ago to leave the campaign in the hands of the government's anti-drug agency.
Officials said slain drug suspects had put up violent resistance. "It has been the desire of the PDEA that PNP will return in the fight against illegal drugs", PDEA Director Aaron Aquino said.
Duterte had twice suspended the police force's lead role in the war on illegal drugs. "These are the only (units) allowed to conduct anti-drug operation", he added. "May the justice of God come upon those responsible for the killings!" the statement said.
Memorandum Order 17 overrules the October 10 memorandum signed by Duterte, which instructed the PNP to merely maintain police visibility while the PDEA conducts its nationwide operations against illicit narcotics trade.
"We will be multipliers of the PDEA...we will be on active support of the PDEA".
Human Rights Watch deputy director in Asia Phelim Kine said Duterte's deadly war on drugs resulted in the extrajudicial executions of an estimated 12,000 people, mostly from poor families.
With cops back in the drug war, it is unlikely that the Philippine Drug Enforcement Agency can stop police abuses despite its lead role in the anti-narcotics campaign, a rights group said.
At the time of demoting the PNP, Duterte described the force as being "corrupt to the core".