The leader of the Philippines has expressed regret after insulting Barack Obama by calling him the "son of a whore".

President Rodrigo Duterte said he regretted that his comments came across as a personal attack on the US president.

In a statement, he said: "While the immediate cause was my strong comments to certain press questions that elicited concern and distress, we also regret it came across as a personal attack on the US President.

"Our primary intention is to chart an independent foreign policy while promoting closer ties with all nations, especially the US with which we have had a long standing partnership." 

The two men were due to meet for the first time on Tuesday afternoon at the ASEAN summit in Laos.

But a White House spokesman said the talks had been scrapped after Mr Duterte insulted Mr Obama.

On Monday, the Filipino leader called Mr Obama "a son of a whore" as he warned him not to raise questions about extrajudicial killings.

Mr Duterte made the comment when asked by a reporter at a press conference how he would explain himself if Mr Obama did raise the issue.

"I don't give a s*** about anybody observing my behaviour," he said.

"I am a president of a sovereign state and we have long ceased to be a colony.

"I do not have any master except the Filipino people, nobody but nobody.

"You must be respectful. Do not just throw questions. Son of a whore, I will swear at you in that forum."

More than 2,400 suspected drug traffickers and users have been executed since Mr Duterte launched a war on drugs.
He took office at the end of June.   

Mr Duterte added that his country had not received an apology for alleged misdeeds committed during the US colonisation of the Philippines in the last century.

Obama, who is in Laos for meetings with South Asian leaders, will instead meet with South Korean President Park Geun-hye.