US President Joe Biden apologized Wednesday for exploding at a reporter who questioned his several hour meeting with Russian President Vladimir Putin.

Before leaving Geneva on Air Force One, Biden addressed a group of reporters and said that he owed Kaitlan Collins "an apology."

"I shouldn't have been such a wise guy with the last answer I gave," Biden said.

On Wednesday, Biden snapped at Collins, a CNN reporter, for asking: "Why are you so confident (Putin) will change his behavior, Mr. President?”

A clearly annoyed Biden, turned back.

“I’m not confident I’m going to change his behavior. What the hell? What do you do all the time?” Biden snapped.

Biden walked back toward the reporter, holding a finger up.

“When did I say I was confident? I said….let’s get it straight….I said, ‘What will change their behaviour is if the rest of the world reacts to them and it diminishes their standing in the world,'” he said.

Biden added, “I’m not confident of anything. I’m just stating a fact.”

The reporter restated her question using specific examples of how Putin’s “past behaviour has not changed” and charging that the Russian leader had denied any wrongdoing in a post-meeting press conference.

She asked Biden, “How did that (constitute) a constructive meeting?”

Biden did not mince his words in response, saying “If you don’t understand that, you’re in the wrong business.”