HANGZHOU, China: After being called an obscenity by the president of the Philippines, President Barack Obama cancelled a meeting with the leader, Rodrigo Duterte, scheduled for Tuesday.

Duterte had threatened to curse out the US commander in chief if Obama raised the issue of extrajudicial killings by Philippine authorities in a sweeping crackdown on drug trafficking. Speaking to reporters, Duterte, who took office in June, said the Philippines is a "sovereign state and we have long ceased to be a colony," according to the Associated Press.

He added that: "I do not have any master except the Filipino people, nobody but nobody. You must be respectful. Do not just throw questions. 'Putang ina' I will swear at you in that forum." That is the Tagalog phrase for "son of a bitch" or "son of a whore."

Asked to respond during a news conference after the Group of 20 Summit in China, Obama said earlier on Monday that he had been told of Duterte's comments, but the US president shrugged it off as another in a line of "colourful statements" from Duterte.