US President Donald Trump has said he could declare a national emergency to build a US-Mexico border wall without the approval of Congress.
It came after he met senior Democrats, who refused his requests for funding.
The stand-off has seen Mr Trump withhold support for a bill to fully fund the government until he gets money for the border wall.
He said he was prepared for the partial government shutdown – now in its third week – to last years.
Around 800,000 federal workers have been without pay since 22 December.
Trump aides and lawmakers will meet later on Saturday in a fresh bid to resolve the impasse.
What happened in Friday’s meeting with Democrats?
The Republican president initially gave a positive account of the 90-minute meeting at the White House, describing it as “very productive”.
But when asked whether he had considered using emergency presidential powers to bypass congressional approval of funding, Mr Trump said he had.
“I may do it. We can call a national emergency and build it very quickly. That’s another way of doing it.”
“I’m very proud of doing what I’m doing,” the president added. “I don’t call it a shutdown, I call it doing what you have to do for the benefit and safety of our country.”
House Speaker Nancy Pelosi said Friday’s meeting had been “contentious”, while Senate Democratic leader Chuck Schumer said: “We told the president we needed the government open. He resisted.”
What’s the background?
Democrats, who now hold the majority in the House, passed spending bills on Thursday to reopen the government, including $1.3bn (£1bn) of border security funds until 8 February.
But the legislation cannot take effect unless it passes the Republican-controlled Senate, where leader Mitch McConnell said his party would not back any measure without the president’s support.
The Kentucky senator called the Democratic budget “a time-wasting act of political posturing”.
In Friday’s news conference, Mr Trump also told reporters he might consider asking his cabinet to decline a $10,000 raise that is due to take effect because a pay freeze has expired as an inadvertent result of the shutdown.
The fiscal fiasco began when Congress and Mr Trump failed to reach an agreement over a budget bill in December.
The Republicans had passed an initial funding bill including $5bn (£4bn) for the wall, when they still had a majority in the House, but they could not get the necessary 60 votes in the 100-seat Senate.
Two vulnerable Republican senators up for re-election in 2020 – Cory Gardner of Colorado and Susan Collins of Maine – have broken ranks to back approving the budget and ending the shutdown.