As negotiations over a $US1 trillion ($A1.38 trillion) spending bill drag on, Republican leaders in the US House of Representatives say they'll seek to pass a stop-gap spending bill to avoid a government shutdown early on Saturday.
House Speaker Paul Ryan on Tuesday said the extension would likely last a "handful of days" to allow work on the spending bill to be completed, potentially over the weekend.
Current government agency spending authority expires at midnight on Friday.
Ryan said he did not want to rush the massive appropriations bill to the House floor and that lawmakers should have time to review it.
His predecessor, John Boehner, was often criticised for quickly moving secretly negotiated spending deals to House floor votes without sufficient input from rank-and-file members.
"We're not going to let an arbitrary December 11 deadline stop us from getting this right," Ryan told a news conference.
"We're going to get the best agreement we can possibly get and those negotiations are ongoing. I'm not going to negotiate through the media."
Ryan added that Congress would not start its holiday break until it passes the measure, which sets spending levels for government agencies, the military and discretionary programs through to September 30, 2016.
Republican and Democratic negotiators are still haggling over a number of policy provisions attached to the spending bill, including Republican proposals to tighten screening for Syrian refugees seeking to enter the United States and to allow US crude oil exports for the first time in 40 years.
They also need to deal with a number of expired business tax breaks.
Negotiations toward a massive deal that would make these permanent and cost $US700 billion over 10 years appeared to stall on Monday, prompting House Ways and Means Committee Chairman Kevin Brady to unveil a less ambitious measure that would extend them for two years instead.
