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.
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.
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.