US senators clashed late Friday over a $1.1 trillion federal spending bill, forcing lawmakers to approve an extension of funds to avoid a government shutdown as Republicans delayed a final vote on the must-pass legislation.
Senate Majority Leader Harry Reid sought to move quickly on the spending measure. He and others were eager to wrap up deliberations and head home for the holidays with government funding intact.
And President Barack Obama said he was "hopeful" the Senate would pass the bill and send it to his desk for his signature.
Reid and Senate Minority Leader Mitch McConnell expressed hope that a deal would be reached for a final vote Friday on the bill funding nearly all federal operations through next September, which passed the House of Representatives on Thursday.
But conservatives, furious that the spending bill failed to roll back Obama's recent unilateral immigration action to shield millions from deportation, demanded an opportunity to amend the measure.
When Reid objected, Republicans signalled they would push a final vote to Monday or later.
"If anybody has the gumption to stand up and object to this abuse of process, they're (accused of) shutting the government down? What planet are we on here?" an irate Republican Senator Jeff Sessions said.
With government funding set to expire midnight Saturday, Congress needs to pass another short-term patch.
The House on Friday narrowly passed an extension until next Wednesday, but amid the acrimony in the Senate no extension deal was finalized.
If there is no agreement by late Saturday to extend funding, the government could plunge into shutdown.
"We are at the mercy of Republican objections," a Senate Democratic leadership aide said.
The Senate is now scheduled to convene on Saturday for a series of votes and to possibly ease the impasse.
A Republican aide said Reid's decision to hold votes on a handful of controversial nominees, including Obama's pick for US surgeon general, is also causing Republicans to stall.
In October 2013, a bitter budget clash between Republicans and Democrats triggered a 16-day government shutdown.
Fueled by their anger over Obama's health care law, many Republicans refused to accept a budget agreement unless it placed limitations on so-called Obamacare.
The shutdown cost 6.6 million in lost workdays for furloughed federal workers, amounting to $2.0 billion in lost productivity, the White House said in a report.
Among the many results of the shutdown, Alaskan crab fisherman lost thousands of dollars a day as their season could not open on time as government officials were not able to set quota sizes.
US National Parks which were closed during the shutdown lost $500 million in lost visitor spending, the report said.
And the shutdown forced the NASA space agency and the National Institutes of Health to furlough four out of five Nobel-prize winning researchers employed by the government.