Philippine President Rodrigo Duterte expressed “regret” on Tuesday after he publicly hurled a profanity at President Obama, prompting the White House to cancel their scheduled meeting.

Duterte had called Obama a “son of a b–” as he warned the American president on Monday to not challenge him over the extrajudicial killings of more than 2,000 suspected drug dealers and users in the Philippines. A reporter had asked the new leader how he would explain the violent war on drugs to Obama.

“I am a president of a sovereign state and we have long ceased to be a colony,” Duterte replied. “I do not have any master except the Filipino people, nobody but nobody.”

The Filipino president then cautioned that Obama “must be respectful” and “not just throw questions.”

Putang ina, I will swear at you in that forum,” he said, using the Tagalog phrase for “son of a b–.”

Letting his temper fly is not unusual for the Filipino president, who has controversially made declarations calling Pope Francis a “son of a whore” and labeling Secretary of State John Kerry “crazy.”

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But the timing of his remarks was especially unfortunate, given that he was just about to fly to the ASEAN summit in Laos, where the meeting with Obama had been planned. It is also Duterte’s first overseas trip since taking office.

“I do not want to quarrel with the most powerful country on the planet,” Duterte told reporters after arriving in Laos’ capital, Vientiane, on Monday night, according to the Associated Press.

But he apparently followed up by suggesting an interrogation of his civil liberties record would be thrown right back at Obama. “Washington has been so liberal about criticizing human rights, human rights, and human rights. How about you? I have so many questions also about human rights to ask you,” said Duterte. “People who live in glass houses should not [throw stones].”

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On Tuesday, the Philippine president released an official statement through his spokesman, acknowledging that his remarks had “elicited concern and distress.”

“We also regret it came across as a personal attack on the U.S. president,” Duterte said in the statement.

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The Philippines also said that its meeting with the White House had been postponed—not canceled—in a decision that was “mutually agreed” upon, according to the statement.