Senate Majority leader Harry Reid has warned that his Democratic-led chamber will reject a House Republican bill to avert a government shutdown.
Early on Sunday, the Republican-led House of Representatives passed its amended version of the Senate bill, removing funding from President Barack Obama’s healthcare law.
There is now less than 48 hours to avert a shutdown, which will begin on Tuesday if no spending bill is passed.
The Senate is not due to meet again until Monday afternoon.
In a statement, Senator Harry Reid said that “after weeks of futile political games from Republicans, we are still at square one”.
Harry Reid added that Republican efforts to change the bill – that would delay the healthcare law for a year and repeal a tax on medical devices – were pointless.
Speaking for the president, White House spokesman Jay Carney said: “Any member of the Republican Party who votes for this bill is voting for a shutdown.”
The president, he said, would also veto the Republican bill.
However, House Republicans went ahead with the changes, ignoring the veto threat and passing the bill in a late-night session by 231 votes to 192.
The Senate is controlled by Barack Obama’s Democratic party, while the Republicans hold the majority in the House of Representatives.
“House and Senate like two locomotives barreling toward one another … in slow motion,” tweeted Republican Representative Scott Rigell.
The looming shutdown ,which would be the first in 17 years, is one of two fiscal crises facing the US government. On October 17, the US treasury department’s authority to borrow money to fund its debt obligations expires unless Congress approves a rise in the so-called debt ceiling.
On Friday, President Barack Obama urged House Republicans to pass the Senate’s stopgap budget bill and to extend the debt limit, and demanded they not threaten to “burn the house down because you haven’t gotten 100% of your way”.
Barack Obama said if the nation were to default on its debt, it would have a “profound destabilizing effect” on the world economy.
“Voting for the treasury to pay its bills is not a concession to me,” Barack Obama said.
“No-one gets to hurt our economy… just because there are a couple of laws [they] don’t like.”