Biden apologizes for being 'short' with reporter

Biden had a testy exchange with CNN reporter Kaitlan Collins when she asked Biden why he thought Putin would "change."

"What the hell. What do you do all the time," Biden said during that exchange. "Let's get it straight. I said what will change their behavior is if the rest of the world reacts to them and it deminishes their standing in the world," Biden clarified.

Biden walked over to reporters just prior to his departure from Geneva for being so "short" with Collins.

"I owe my last questioner an apology. I shouldn't have been such a wise guy," Biden said prior to boarding Air Force One.

Both Biden and Putin said Moscow and Washington shared a responsibility for nuclear stability, and would hold talks on possible changes to their recently extended New START arms limitation treaty.