Philippines' President Rodrigo Duterte, whose use of profanity has become his trademark, says he will stop cursing altogether after receiving a direct order from God.

Duterte, who has at separate times called Pope Francis and US President Barack Obama "sons of bitches", has vowed he will not spew expletives again.

The president made the pledge upon arrival in his southern hometown of Davao city late on Thursday from a trip to Japan.

He claimed on the flight while he was looking at the sky and everyone was sound asleep, he heard a voice that said - "If you don't stop epithets, I will bring this plane down now."


READ MORE: Duterte tells Obama to 'go to hell'


"And I said, 'Who is this?' So, of course, 'It's God'," said Duterte.

"So, I promise God to ... not express slang, cuss words and everything. So you guys hear me right always because [a] promise to God is a promise to the Filipino people."

Duterte's vow was met with applause, but he cautioned: "Don't clap too much or else this may get derailed."

He has repeatedly levelled profane tirades against Obama, UN Secretary-General Ban Ki-moon, a few outspoken opposition politicians and human rights advocates, while heaping praise on Chinese and Russian leaders.

Duterte has also repeatedly used profanities while threatening to kill drug dealers as part of his war on illegal drugs that has left thousands dead since he took office at the end of June.

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There were no expletives in his Thursday speech, but Duterte still sounded mean towards critics.

When asked for his message to a Filipino beauty queen who won the recent Miss International pageant, Duterte said he was proud. "Many Filipinas are beautiful, but all of you there in the human rights commission are ugly."

However, asked if the days of his cursing the United States and the European Union are over, Duterte did not give a clear answer.

"I do not want anybody reading my mind because I couldn't make a smart move any more. But it's all calibrated - it's all about timing," Duterte said.

He shocked the dominant Roman Catholics in the country last year when he fired an expletive while expressing his disgust over a major traffic jam that trapped him while Pope Francis was visiting Manila.

"I wanted to call - 'Pope, you son of a bitch, go home. Don't visit here any more,'" he told a group of supporters.


READ MORE: Duterte unleashes more profanity at the EU


He later apologised after Filipino bishops expressed shock and outrage.

It is not certain if the 71-year-old president, who has been compared to US Republican presidential candidate Donald Trump because of his brash language, can keep his promise.

Duterte made a similar pledge in June when it became evident that he had won the May 9 presidential election overwhelmingly on a pledge to end crime, especially illegal drugs, and corruption.

He said then he was enjoying his last moments as a "rude person" because "when I become president, when I take my oath of office ... that will be a different story. There will be a metamorphosis".

But it didn't take long for Duterte to break that promise.

Duterte's first 100 days

Source: Agencies