A deal to raise the federal debt ceiling and avoid the first ever U.S. default is "very close" and a vote on a bipartisan measure could take place as soon as Sunday night, top Senate Leaders said.

Senate Majority Leader Harry Reid said Sunday afternoon that he hopes a vote can happen Sunday evening to avoid a default by an Aug. 2 deadline, according to Reuters.

Sen. Mitch McConnell said a deal is "very close" on CNN's "State of the Union" Sunday morning.

Top level negotiations were continuing on Sunday after an early afternoon attempt by Reid to see if one of his proposals would have enough votes to clear the Senate. It fell short of the 60 "ayes" needed to overcome a Republican Party filibuster. It could only manage a 50-49 vote in favor.

The deal currently being negotiated by McConnell and Vice President Joe Biden included a rise in the federal debt limit in two stages, for a total of $2.2 trillion. The increase would be large enough not to need another raise beyond the 2012 general election.

On Friday, the Senate blocked a bill passed by the House handily, setting the stage for further negotiations.

Republicans and Democrats have been in discussions for months regarding the debt limit as the deadline has approached.