From NBC's Kelly O'Donnell and Libby Leist
Aides to Sen. Tom Coburn say the Oklahoma Republican "has decided to take a break" from the "Gang of Six" negotiations on the federal deficit.
The three Republicans and three Democrats in the group have been negotiating for months to come up with a long-term debt reduction plan.
Coburn claims the Gang of Six has "reached an impasse" and that he "is disappointed the group has not been able to bridge the gap between what needs to happen and what senators will support."
Aides claim Coburn has not abandoned the effort for good, but he did not attend the group's meeting today.
Coburn's office says he "still hopes the Senate will, on a bipartisan basis, pass a long-term deficit reduction package this year" and that he "looks forward to working with anyone who is interested in putting forward a plan that is specific, balanced and comprehensive."
A Democratic source familiar with the talks says that Coburn brought new issues to the table at the last minute that prevented the group from coming to a deal and gave the members the indication he was not negotiating in good faith.
Democratic members of the gang are Sens. Dick Durbin of Illinois, Mark Warner of Virginia and Budget Committee Chairman Kent Conrad of North Dakota. The other Republicans in the group are Sens. Saxby Chambliss of Georgia and Mike Crapo of Idaho.
The Senate group is separate from the bicameral negotiatons being led by Vice President Joe Biden. Those talks have been described by Republican Leader Mitch McConnell as the more critical process because of the need for the direct involvement of the White House.