President Rodrigo Duterte on Tuesday told barangay officials in Davao City that killing suspected lawbreakers in self-defense is "not an extrajudicial killing", so they should "go ahead".

"If you think that your life is in danger, go ahead…by all means kill…hindi iyan extrajudicial killing," he said in a mix of Visayan and English during a Christmas gathering in the city.

He said he was able to clean up Davao City because of the cooperation of barangay officials.

Local officials struck fear into the hearts of criminals, particularly those involved in the illegal drug trade, he added.

"Either ikaw ang mamatay o ang droga. Mamili ka. (Either you die, or drugs will. Choose.) I will always defend you. Don’t be afraid of charges filed against you, that goes with the military and the police…and that is until the end of my term," Duterte said.

Duterte earlier said that during his term as mayor of Davao City, he personally killed suspected criminals to set an example for police.

He also acknowledged killing suspected criminals, such as kidnappers, in Davao City during his third month as mayor.

"'Pag labas ng carbine sa window, pinagbabaril namin. Totoo iyan…mayor ako ng Davao, hindi ako papayag na mangyayari iyan sa amin," he said during an ambush interview on December 17.

(I'd shoot them from the window using the carbine. That's true. I was the mayor of Davao and I wasn't going to let that happen.)