A bitterly divided US congress is hurtling towards a government shutdown this weekend amid a stand-off over demands by Democrats for a solution on legislation to protect about 700,000 younger immigrants from being deported.
Democrats in the US senate have served notice they will filibuster a four-week, government-wide funding bill that passed the House on Thursday evening.
The Democrats are seeking to shape a subsequent measure, but have been accused of being responsible for the looming shutdown.
US president Donald Trump said Senate Democrats are focused on "illegal immigration and weak borders".
He said on Twitter: "Government Funding Bill past (sic) last night in the House of Representatives. Now Democrats are needed if it is to pass in the Senate - but they want illegal immigration and weak borders."
He added: "Shutdown coming? We need more Republican victories in 2018!"
Government Funding Bill past last night in the House of Representatives. Now 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!— Donald J. Trump (@realDonaldTrump) January 19, 2018
Republicans controlling the narrowly divided chamber argued that Democrats are holding the entire government hostage over demands to protect "Dreamer" immigrants brought to the country illegally as children under the Deferred Action for Childhood Arrivals (DACA) programme.
Senate majority leader Mitch McConnell said: "Democratic senators’ fixation on illegal immigration has already blocked us from making progress on long-term spending talks.
"That same fixation has them threatening to filibuster funding for the government."
In the House, Republicans forced the measure through on a mostly party-line 230-197 vote after making modest concessions to chamber conservatives and defence hawks. House Speaker Paul Ryan immediately summoned reporters to try to pin the blame on top Senate Democrat Chuck Schumer of New York.
A test vote on a filibuster of the measure by senate Democrats appeared likely before the shutdown deadline of Friday at midnight. Mr Schumer was rebuffed in an attempt to vote on Thursday night.
Mr Schumer said: "We can’t keep kicking the can down the road", and insisted 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 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 (£57 billion) disaster aid bill.
A shutdown would be the first since 2013, when tea party Republicans sought to use a must-pass funding bill to try to force then-President Barack Obama into delaying implementation of his signature health care law.
Congress must act by midnight Friday or the government will begin immediately locking its doors. In the event of a shutdown, food inspections, federal law enforcement, airport security checks, and other vital services would continue, as would Social Security, other benefit programmes and military operations. But federal workers would not be paid.