MANILA, Philippines (AP) — The foul-mouthed Philippine president, who once called the pope a "son of a bitch" and told Barack Obama to "go to hell," says he has promised to God he won't spew expletives again.

President Rodrigo Duterte's foul mouth has become a trademark of his political persona as he peppered his speeches with profanities.

Duterte says that while flying home from a state visit to Japan, he was looking at the sky while everyone was sound asleep and he heard a voice that said "'if you don't stop epithets, I will bring this plane down now."

He explained: "And I said, 'Who is this?' So, of course, 'it's God.'"

He says he promised to God and the Filipino people not to use any more slangs or cuss words.