​​Two months ago, Philippine President Rodrigo Duterte publicly read out the names of a town mayor and more than 150 other officials he accused of involvement in drug trafficking. On Friday, the mayor and nine of his men were killed in a clash with police, in the deadliest operation in Duterte's anti-drug crackdown.

Police estimate that more than 3,600 suspected drug dealers and users have been killed since Duterte took office on June 30.

After his name was read out in August, Mayor Samsudin Dimaukom of Datu Saudi Ampatuan township in southern Maguindanao province turned himself in to police and denied involvement. He told the media he was fighting illegal drugs himself and supported Duterte's crackdown.

Dimaukom and the nine others were killed at dawn Friday after they opened fire from a van and an SUV on officers manning a checkpoint in Makilala town in North Cotabato province, police Superintendent Bernard Tayong said.

"Our men were forced to retaliate when the heavily armed suspects who were on board two vehicles began firing at them," said Senior Superintendent Albert Ignatius Ferro, who heads a police anti-illegal drugs force.

Filipino demonstrators (foreground) mimic an extrajudicial killing crime scene as police officers stand guard during a protest in front of the Philippine National Police (PNP) headquarters in August.

Police found an M16 rifle, four pistols, a 12-gauge shotgun, ammunition and at least 13 small plastic packs of suspected methamphetamine, a stimulant drug locally known as shabu, from the bullet-peppered vehicles of the suspects, police deputy regional chief Senior Superintendent Leonardo Suan said.

Police said they had received information that Dimaukom's group was planning to transport a "huge" amount of methamphetamine from Davao city, Duterte's hometown, to Datu Saudi Ampatuan town.

Duterte's crackdown has drawn international concern over extrajudicial killings, but he has repeatedly dismissed criticisms and vowed to keep his election promise to rid the country of illegal drugs. He originally said he would do so in six months, but extended that deadline by half a year, saying he was overwhelmed by the magnitude of the drug menace.

Unprecedented crackdown

The extent of Duterte's crackdown is unprecedented in the country. Since he took office, police have arrested more than 31,600 drug suspects, and more than 750,000 people, mostly drug users, have surrendered to authorities, largely due to fears they could end up dead. Police have visited more than 2.6 million homes to urge suspected drug users and dealers to stop.

Philippine President Rodrigo Duterte's crackdown has drawn international concern over extrajudicial killings, but he has repeatedly dismissed criticisms and vowed to keep his election promise to rid the country of illegal drugs. (Noel Celis/AFP/Getty Images)

On Wednesday, police launched a new phase of the crackdown called Double Barrel, which they say will focus on "high-value targets" such as drug lords and those involved in large-scale drug production and trafficking.

Duterte said late Thursday he still has a long list of drug suspects including politicians, village officials, judges and policemen, showing a thick pile of documents.

"This is the drug industry in the Philippines," Duterte said. "I can't deal with this alone," he said, appealing to the public for help.

He appeared to issue another warning, saying that thousands more drug suspects may end up dead. He expressed disgust over criticism levelled against him while he battles a drug menace that he said has left many police officers dead.

"And to say that I should behave and keep on harping on that ... I'll tell you I will triple it," Duterte said. "If my wishes aren't followed ... you can expect about 20,000 or 30,000 more."

"There is a war going on, I am losing two, three policemen a day. It's a war, how could it be ... genocide, killing a helpless person there, kneeling," he said. "There's none of that, we do not gather children and young men and shoot them."