A Senate source tells CBS News that the incident occured after the picture was taken, as Cheney chatted with Republican senators. Leahy approached the vice president and, apparently joking, asked if Cheney wasn't talking to Democrats.
Senate aides with knowledge of the encounter said the vice president then confronted Leahy about some of the Democrat's criticism about alleged improprieties in Iraq military contracts awarded to Halliburton Co. Cheney, who as vice president is president of the Senate, is a former CEO of Halliburton.
Leahy has called for an investigation after an suggesting the vice president's office was somehow involved in awarding a lucrative contract for work in Iraq.
In the encounter Tuesday, Leahy responded by criticizing the White House for standing by allies who had accused Democrats of being anti-Catholic last year in opposing one of President Bush's judicial nominees, said one Senate aide, speaking on condition of anonymity.
Cheney then responded, "F--- off" or "F--- you," the aide said.
That account was backed by another aide, also speaking on condition of anonymity.
During the fight over confirming Alabama's William Pryor, a conservatice group ran an ad accusing Democrats who opposed Pryor as anti-Catholic. Republican Sen. Rick Santorum of Pennsylvania said Democrats "litmus test" on the issue of abortion was "ultimately a religious one."
Leahy confirmed that the confrontation took place but would not provide details.
"I think he was just having a bad day," Leahy said. "I was kind of shocked to hear that kind of language on the floor."
Cheney's office also wouldn't go into detail, but confirmed the two men traded remarks.
"That doesn't sound like language that the vice president would use, but there was a frank exchange of views," said Kevin Kellems, a spokesman for Cheney.
Similar frank talk has been recorded in the high chambers of American government before. Tapes of Lyndon Johnson are sprinkled with profanity. In the Watergate tapes, Richard Nixon swore frequently. One printable example: Nixon's hope that "Congress will keep its God-damn cotton-pickin' hands off that trial."