US President Donald Trump and Senate Democratic leader Chuck Schumer have held eleventh-hour talks to avert a government shutdown.
The discussions came as Washington is locked in a partisan stalemate over politically fraught legislation to protect about 700,000 younger immigrants from being deported.
Republicans and Democrats in Congress and the White House traded blame for the possible shutdown with just hours remaining before the midnight deadline. Mr Trump phoned the New York senator to invite him to the White House to try to reach an accord.
Democrats in the Senate have served notice that they will filibuster a four-week, government-wide funding bill that cleared the House on Thursday evening. That could expose them to charges that they are responsible for a shutdown, but they point the finger at Republicans instead.
"They're in charge," Mr Schumer said on Friday as he entered his office. "They're not talking to us. They're totally paralysed and inept. There's no one to negotiate with."
Republicans controlling the narrowly split chamber argue that it is the Democrats who are holding the government hostage over demands to protect "dreamer" immigrants brought to the country as children and now here illegally.
And the White House piled on, trying to paint the impending action as the "Schumer shutdown". But officials said the president has been working to avert one.
As a shutdown loomed, the White House said that Mr Trump would not leave for a planned weekend trip to Florida. The president had been set to leave on Friday afternoon to celebrate the one-year anniversary of his inauguration at his Palm Beach estate.
The impact of the potential shutdown on the planned trip by Mr Trump and much of his Cabinet to the World Economic Forum in Davos, Switzerland, next week was still undetermined.
Mr Trump entered the fray early on Friday morning, mentioning the House-approved bill on Twitter, adding: "Democrats are needed if it is to pass in the Senate - but they want illegal immigration and weak borders. Shutdown coming? We need more Republican victories in 2018!"
Mr Trump has given Congress until March 5 to save the Obama-era Deferred Action for Childhood Arrivals programme protecting young immigrants, so "there is absolutely no reason to tie those things together right now," budget director Mick Mulvaney said at the White House.
On Capitol Hill, senate majority leader Mitch McConnell, said he hoped to vote on the House-passed bill soon, and added that Americans at home would be watching to see "which senators make the patriotic decision" and which "vote to shove aside veterans, military families and vulnerable children to hold the entire country hostage... until we pass an immigration bill."
A Senate Republican aide said Mr McConnell was not attending the White House meeting because Mr Trump had only issued the invitation to Mr Schumer.
In the House, Republicans muscled the measure through on a mostly party-line 230-197 vote after making modest concessions to chamber conservatives and defence hawks.
The chamber backed away from a plan to adjourn for a one-week recess on Friday afternoon, meaning the Republican-controlled House could wait to see if a last-minute compromise would be reached requiring a new vote.
A test vote on a filibuster by Senate Democrats appeared likely before the shutdown deadline. Mr Schumer was rebuffed in an attempt to vote on Thursday night.
"We can't keep kicking the can down the road," said Mr Schumer, insisting on more urgency in talks on immigration. "In another month, we'll be right back here, at this moment, with the same web of problems at our feet, in no better position to solve them."
The short-term measure would be the fourth stopgap spending bill since the current budget year started in October. A pile of unfinished Capitol Hill business has been on hold, first as Republicans ironed out last autumn's tax bill and now as Democrats insist on progress on immigration.
Talks on a budget deal to ease tight spending limits on both the Pentagon and domestic agencies are on hold, as is progress on a huge 80 billion dollar-plus disaster aid bill.
House Republican leaders sweetened the pending stopgap measure with legislation to extend for six years a popular health care programme for children from low-income families and two-year delays in unpopular "Obamacare" taxes on medical devices and generous employer-provided health plans.