The Senate will vote Saturday on proceeding to a bill to raise the debt ceiling by $1 trillion.
Senate Majority Leader Harry Reid (D-Nev.) on Thursday filed a motion to set up the vote, which would test whether he has the support to extend the debt ceiling through the end of 2014.
It's unclear whether Reid will have the votes. The measure would raise the debt ceiling but would not cut spending, and it could be difficult for Republicans to back a "clean" debt-ceiling hike.
Senate Minority Leader Mitch McConnell (R-Ky.) said Reid's bill "just won't fly" with Republicans.
"It’s irresponsible to do nothing about the debt, and it’s irresponsible to stir up anxiety about defaulting on the debt," McConnell said.
The House also appears poised to vote on a shorter extension of the debt ceiling. House Republicans are discussing a six-week extension of the debt ceiling. It was not immediately clear if the House measure would be a "clean" hike.
But if the House does move forward with that bill, it could allow Senate Republicans to demand a vote on that measure.
The House bill would not end a government shutdown that entered its 10th day Thursday. Reid's bill also would not end the shutdown.
The Treasury Department and White House have warned that, if the limit is not lifted, the government could default on its debt, leading to a recession.