White House officials previously said Obama would confront Duterte about his country’s handling of drug dealers, including extrajudicial killings, which are government executions without the benefit of judicial proceedings.

“Who does he think he is? I am no American puppet. I am the president of a sovereign country and I am not answerable to anyone except the Filipino people,” Duterte scoffed in a speech Monday. “Son of a bitch, I will swear at you.”

The firebrand president was answering a reporter’s question about how he intended to explain the extrajudicial killings to Obama, before boarding a plane to Laos for the Association of South-east Asian Nations summit.

“You must be respectful. Do not just throw away questions and statements. Son of a whore, I will curse you in that forum,” Duterte was quoted by as saying by Agence-France Presse. “We will be wallowing in the mud like pigs if you do that to me.”

When his comments reached the Obama camp, the US president initially said he was asking his staff to find out whether holding the meeting as scheduled would be useful.

“What I’ve instructed my team to do is to talk to their Philippine counterparts to find out, is if this in fact a time where we can have some constructive, productive conversations,” Obama said at a news conference at the end of a G20 summit in the eastern Chinese city of Hangzhou.