It is a part of any United States president’s job to smile blithely while reporters loudly shout questions as they are ushered out of the room at the end of a press availability.

But on Monday, President Joe Biden tripped up when he responded with a profane insult to a pointed query from a Fox News reporter.

The president was in the East Room of the White House for a meeting of his Competition Council, an economic group tasked with helping American consumers deal with high prices by changing regulations and enforcing competition laws.

After Biden’s remarks, reporters in the room shouted questions as they were being ushered out.

Fox News’ Peter Doocy, whose network has been relentlessly critical of Biden, asked Biden about US inflation, which is at a nearly 40-year high and has hurt the president’s public approval rating.

Doocy called out, “Do you think inflation is a political liability ahead of the midterms?”

“It’s a great asset — more inflation,” Biden said in a low tone, appearing to speak to himself. Then added, “What a stupid son of a b***h” with a slight shake of his head.

Indeed, surging US inflation is a growing political risk for Biden and his Democratic Party which could lose its majority in the US Congress in the upcoming November elections. Persistent inflation has the effect of reducing people’s purchasing power and raising food, fuel and housing costs for households.

The president’s comments were captured on video and by the microphone in front of him.

Doocy laughed it off in a subsequent appearance on his network, joking, “Nobody has fact-checked him yet and said it’s not true.”

He said he did not hear the president’s remarks at the time as he was being ushered out of the room.

Doocy told Fox News’ Sean Hannity that Biden called him about an hour after the incident to apologise. Doocy said Biden told him, “It’s nothing personal, pal.”

The White House did not immediately respond to a request by The Associated Press for comment.

White House officials have insisted repeatedly that they are focused on curbing inflation, with Biden reorienting his economic agenda to address the issue.

But the president has shown a willingness to challenge a media that he deems to be too critical, especially Fox News and Doocy.

At his news conference last week, Biden said to Doocy with sarcasm: “You always ask me the nicest questions.”

“I have a whole binder full,” the reporter answered.

“I know you do,” Biden said. “None of them make a lot of sense to me. Fire away.”