President Barack Obama has canceled a scheduled meeting with new Philippine President Rodrigo Duterte after the obscenity-prone leader threatened Monday to make a scene at a regional summit in Laos if Obama challenged him on his country’s policy of summary executions.

“Son of a bitch, I will swear at you,” Duterte warned, according to The Associated Press.

The heated response was prompted by a reporter who asked Duterte how he would explain the extrajudicial killings that have soared in the island country of nearly 100 million people in the two months since he took office.

“I am a president of a sovereign state and we have long ceased to be a colony. I don’t have any master except the Filipino people, nobody but nobody. You must be respectful. Do not just throw away questions. Putang ina, I will swear at you in that forum,” he said, using a Tagalog phrase to insult Obama. It could also be translated as “son of a whore.”

Before calling off the meeting scheduled for Tuesday, Obama initially downplayed the Philippine president’s aggressive words.

“I’ve seen some of those colorful statements in the past. And clearly he’s a colorful guy,” he said Monday.

But Obama also hinted that he would, in fact, question the policy on extrajudicial killings “if and when” it comes to the table at the

Association of Southeast Asian Nations Summit this week.

“We recognize the significant burden that the drug trade plays not just in the Philippines but around the world, and fighting narcotrafficking is tough,” Obama told reporters at the G20 Summit. “But we will always assert the need to have due process and to engage in that fight against drugs in a way that’s consistent with basic international norms.”

Since taking office on June 30, Duterte has launched an aggressive but simple campaign against suspected drug dealers and traffickers in his country: “Kill them all.”

In the Philippines, hundreds of dead bodies have turned up on the streets, sometimes with crudely written notes of the person’s alleged crime, Public Radio International reported in August.

Philippine National Police chief Ronald dela Rosa disclosed that more than 1,700 people have been killed since July 1, according to Amnesty International.

Duterte since his inauguration has encouraged police “to double your efforts …triple them if need be,” and has applauded the street killings that human rights groups say amount to extrajudicial executions.

Duterte on Monday remained defiant in the face of criticism.

“We will continue and I will continue, and I don’t give a s**t about anybody observing my behavior,” he said.

This article has been updated with news that Obama canceled the meeting.