White House budget director Mick Mulvaney. (Andrew Harnik/AP)

White House budget director Mick Mulvaney said Thursday that he hopes to use negotiations to keep the government open past April 28 in an effort to force Democrats to back some funding for creating a new wall along the U. S-Mexico border — a risky move that could provoke a spending showdown with congressional Democrats next week.

Mulvaney said the White House would be open to funding some of the Democrats’ priorities — such as paying insurance subsidies under the Affordable Care Act — if Democrats agree to fund some of the more controversial parts of President Trump’s agenda, notably the border wall.

The new request threatens to undermine weeks of negotiations between Republican leaders and Democrats in Congress to pass a stopgap spending bill to avoid a government shutdown. The negotiations so far have excluded talk of the border wall, which Republicans have argued should be taken up later to keep the government open.

“We have our list of priorities,” Mulvaney said at an event hosted by the Institute of International Finance. “We want more money for defense. We want to build a border wall. We want more money for immigration enforcement, law enforcement.”

Mulvaney stopped short of saying that the White House would refuse to sign a spending agreement that does not include those priorities, but he made clear that he expects Democrats to reopen talks. Democrats saw Mulvaney’s comments as evidence that the White House is meddling to undermine what they described as successful, bipartisan talks.

“Everything had been moving smoothly until the administration moved in with a heavy hand,” said Matt House, a spokesman for Senate Minority Leader Charles E. Schumer (D-N.Y.). “Not only are Democrats opposed to the wall, there is significant Republican opposition as well.”

Republican leaders and members of the House and Senate appropriations committees had hoped to avoid a spending confrontation early in Trump’s administration by negotiating directly with Democrats, whose votes will be necessary to pass any spending bill. Republicans hold a slim 52-to-48 advantage in the Senate, meaning they will need at least eight Democrats to reach the 60 votes required to pass spending measures in that chamber.

Drew Hammill, a spokesman for House Minority Leader Nancy Pelosi (D-Calif.), said the White House comments make it “more difficult” to reach an agreement, arguing that there is intense opposition to the wall from Democrats in both the House and Senate.

Mulvaney said that the White House is willing to negotiate, but only if Democrats bend on funding the wall.

“If they tell us to pound sand, I think that’s probably a disappointing indicator of where the next four years is going to go,” Mulvaney said. “If they tell us, however, that they recognize that President Trump won an election, and he should get some of his priorities funded for that reason, elections have consequences, as folks who win always like to say.”