Duterte pulled the national police from the campaign a month before he hosted a November summit of about 20 world leaders including U.S. President Donald Trump.

Presidential spokesman Harry Roque said Tuesday that Duterte's new memorandum directed the Philippine National Police and other law enforcement agencies "to resume providing active support" to the Philippine Drug Enforcement Agency, a small agency delegated to spearhead anti-drug operations.

Roque said Duterte recognized that the anti-drug campaign had been seriously hampered by PDEA's lack of resources and that there had been a resurgence of drug crimes since police and other law enforcement agencies were directed to leave the crackdown.

Read: Philippines` Duterte Defends Drugs War

Duterte first pulled the 160,000-strong police force from his anti-drug campaign in January amid public outrage over the strangling to death of a South Korean businessman in front of the national police headquarters, allegedly by an officer involved in the crackdown. The officer and other policemen allegedly used the drug campaign as a cover to kidnap the Korean and extort money from his family.

Duterte then said he wanted to cleanse the national police force, which he condemned as "corrupt to the core." He ordered the military and the PDEA to continue the crackdown but later reintroduced the police despite concerns that it remained corrupt.

Nearly 4,000 suspects have been killed, mostly in firefights with police. Duterte and police officials say the victims fought back and placed enforcers in danger. Thousands of arrests of suspects and the wounding of many police underscore the risks faced by enforcers, the president and police say.

Human rights groups, however, have accused police of carrying out extrajudicial killings and covering them up by planting guns on slain suspects, most of whom were poor addicts and drug peddlers. Western governments have also raised alarm over the high number of killings.

Also Tuesday, the Supreme Court continued a public hearing and deliberations on petitions challenging the anti-drug war.

Supreme Court Chief Justice Maria Lourdes Sereno said on a single day, 32 drug suspects were killed in one province in nine hours and a similar number were killed in one city, and that Duterte was quoted as saying that was a good outcome that should happen every day.

Solicitor General Jose Calida responded that Duterte may have been joking.

Efforts are underway by lawmakers, including Duterte's allies in the House of Representatives, to impeach Sereno.

AP