Philippines President Rodrigo Duterte on Tuesday said Sri Lankan counterpart Maithripala Sirisena has vowed to emulate his approach to curbing the drug menace by "killing bastards."

Sirisena was in the Philippines last month for a state visit during which he lauded Duterte's war on drugs.

The campaign, however, has received local and international condemnation for the unexplained killings of thousands of drug suspects. 

"I knew the most basic sorrow and agony of the people is drugs. And we are not buffeted on both sides, we get a double whammy. The [Sinaloa] cartel of Mexico are expanding and the greed for money, easy money, dirty money, increases their appetite everyday," Duterte said in a speech in Davao City.

"If you look at the Philippines, your left side, your left hand is the west, your right hand is the east. On the western side, we have the golden triangle, also a well known drug cartel in Asia and doing now business in the East Asian countries, prompting even the Prime Minister of Sri Lanka say, 'I will follow Duterte. I will kill the bastards,'" he added.

Last year, Sirisena announced plans to deploy the military to tackle drugs, saying that the Philippines has been “successful” with that approach.

"[It's] good that he has a good, shining example," said Duterte.

It is the police, however, that is at the forefront of the Philippines' drug war, along with the Philippine Drug Enforcement Agency and the National Bureau of Investigation.

Apart from tapping the military, Sirisena had also said they will hang drug offenders without commuting their death sentences. (GMA)