“The incident this morning is connected to the current investigation pertaining to the involvement of the mayor and his son in the illegal drugs trade,” national police spokesman Dionaldo Carlos said.

He said six gunmen were killed while police recovered 17 guns and several grenades.

On Monday Duterte gave Espinosa and his son 24 hours to surrender after police arrested five of the mayor’s bodyguards and employees in a drug sting operation.

“Otherwise, an order of ‘shoot on sight’ will be given if they resist and endanger the lives of arresting police officers,” presidential spokesman Ernesto Abella said on television.

The mayor surrendered to police on Tuesday. The son is at large.

The mayor “surrendered to me... (following) orders of the president for him to be shot on sight if he resists,” said national police chief Ronald de la Rosa.

Police claim to have killed more than 400 suspected drug dealers in the month since Duterte took office, but rights groups fear the total could be far higher as vigilantes have joined the spree.

Hundreds of anti-narcotics and human rights groups from around the world called Tuesday for the United Nations to condemn Duterte’s policy.

“International drug control agencies need to make clear to Philippines’ President Roderigo Duterte that the surge in killings of suspected drug dealers and users is not acceptable ‘crime control,’ but instead a government failure to protect people’s most fundamental human rights,” said Phelim Kine , Human Rights Watch’s deputy Asia director.

Philippine Senator Leila M. De Lima, in a speech Tuesday decried what she called the “do-it- yourself justice” system under Duterte.

“We must call for the accountability of state actors responsible for this terrifying trend in law enforcement, and the investigation of killings perpetrated by the vigilante assassins,” she said.

Police chief de la Rosa said Mayor Espinosa had been listed in police records as a “drug protector” whose son controlled the narcotics trade in the Albuera region.

“If you’re listening now Kerwin, your father has already surrendered so you should follow your father,” de la Rosa said in a bizarre live news conference with Espinosa.

“If you don’t surrender you will die, so better surrender because your life is really in danger.”

Espinosa has publicly denied any part in the drug trade but said his son was peddling “shabu” (methamphetamine), which he gets from a jailed Chinese drug trader.

The raid signalled a shift in Duterte’s drug war from running after street-level peddlers and users to powerful regional politicians and foreign drug traffickers.

Duterte has promised to name dozens of governors, mayors and other politicians he says are involved in the drug trade after identifying three police generals and two former police generals who were protecting drug traffickers.

Police said charges had been filed against another mayor from the southern island of Mindanao after he escaped from a police raid last week, when 16 people were arrested 1 million pesos ($21,263) worth of drugs were seized.

Last month, also on national television, Duterte told a businessman at a meeting he would “finish you off” unless he stopped dealing in drugs. The businessman denied the allegations.

Police said more than 100,000 other people have also surrendered to the local authorities and pledged to stop using illegal drugs.

Additional reporting by Reuters and Associated Press