US Vice President Dick Cheney clashed with his successor over the proper role of his office, suggesting Joseph Biden might "diminish" the importance of the vice presidency.
Cheney's pointed remarks were a contrast to the cordial public tone that has prevailed so far as President George W Bush prepares to hand over power to president-elect Barack Obama on January 20.
The outgoing vice president, whose term ends in a month, rejected criticism from vice-president-elect Biden who had said during the election campaign that Cheney had overstepped his constitutional role.
"If he wants to diminish the office of the vice president, that's obviously his call," Cheney said in an interview with Fox News on Sunday.
"President-elect Obama will decide what he wants in a vice president and apparently, from the way they're talking about it, he does not expect him to have as consequential a role as I have had during my time."
During a campaign debate, Biden had called Cheney "dangerous" and said he did not understand the legal status of the vice president's office under the Constitution.
Cheney ridiculed Biden's grasp of the law, citing the Delaware senator's comments.
"He also said that the 'all the powers and responsibilities of the executive branch are laid out in Article I of the Constitution,'" Cheney said.
"Well, they're not. Article I of the Constitution is the one on the legislative branch," he said.