WASHINGTON — Congress is running out of time to keep the government open, with senators in both parties warning that they will likely need to pass another short-term funding bill to prevent a partial shutdown this weekend.

“We’ve just had obstacles every step of the way,” said Sen. Jeanne Shaheen, D-N.H., a member of the Appropriations Committee, cautioning that House Republican demands for certain policy changes are “not realistic” and holding up the process.

Shaheen said another stopgap bill is “part of the discussion” as funding legislation still has not been released and House GOP leaders have promised to wait 72 hours before a vote takes place to let members read it, leaving little time. The Senate will then need unanimous consent to pass it speedily — no sure thing.

Funding for the parts of the government including the Departments of Agriculture, Veterans Affairs, Transportation, Energy and Housing and Urban Development is set to expire at the end of Friday. Other departments, including the Departments of Justice, Labor and Health and Human Services, have a March 8 deadline and face more contentious funding battles.

A White House meeting between President Joe Biden the top four congressional leaders Tuesday yielded some optimism that they were moving toward agreement on a funding package to keep open parts of the government facing the March 1 deadline.

Speaker Mike Johnson, R-La., told reporters Tuesday that top negotiators were “working in good faith” and “quite literally around the clock” to resolve their differences.

“We’re very optimistic,” he said. “We believe that we can get to agreement on these issues and prevent a government shutdown. And that’s our first responsibility.”

Before a lunch meeting with Democrats, Senate Majority Leader Chuck Schumer, D-N.Y., said “We can’t shut down the government” and added that he conveyed to Johnson that a short-term funding bill, also known as a “CR” or continuing resolution, may be necessary.

“To not shut the government down — it means we need CRs and we told that to Johnson,” Schumer said.

It’s unclear whether Johnson accept another short-term bill, although he hasn’t ruled it out. And even if both chambers are on board, rebellious factions could create obstacles to passing it in time for the 11:59 p.m. Friday deadline.

Sen. Rand Paul, R-Ky., told NBC News he would “apply duress” to leaders by blocking speedy votes unless he gets changes to the bill or at least votes on amendments to slash spending.

“I’ll do the same thing I always do which is introduce spending amendments and at least put the Senate on record as to whether they’re for cutting spending,” Paul said.

If there’s another stopgap, it would be the fourth of this fiscal year, which is nearly halfway over, after Congress punted in September, November and January. The September bill sparked a GOP revolt that cost former Speaker Kevin McCarthy, R-Calif., his job. The January measure came after Johnson said he wouldn’t accept another stopgap bill, before reversing course.

“We’re getting close on the first four bills. Hopefully, that won’t require another short-term CR,” Senate Minority Leader Mitch McConnell, R-Ky., told reporters Tuesday. “Hope springs eternal.”

After the separate Senate caucus lunch meetings, Schumer declined to discuss whether a short-term bill was needed and held out hope that leaders would reach a deal soon.

“We’re going to move as quickly as possible. The negotiators of McConnell, myself, Johnson and Hakeem [Jeffries, the House minority leader] met this morning. They’re meeting again this afternoon,” Schumer said Tuesday “We’re getting closer.”

Much of the long and ongoing fight over funding is largely being driven by the House Republican majority, which is demanding a mix of spending cuts and conservative policy provisions to win their support for a full-year spending package.

“The consensus is there on what appropriations should be. It’s simply a matter of eliminating some of the extraneous political stunts that are ongoing in the House,” said Sen. Richard Blumenthal, D-Conn., told reporters.

“I think we may well need a CR,” Blumenthal added.