The Senate took the first step to end the government shutdown on Sunday after a group of moderate Democrats agreed to proceed without a guaranteed extension of health care subsidies, angering many in their caucus who say Americans want them to continue the fight.

In a test vote that is the first in a series of required procedural maneuvers, the Senate voted 60-40 to move toward passing compromise legislation to fund the government and hold a later vote on extending Affordable Care Act tax credits that expire Jan. 1. Final passage could be several days away if Democrats object and delay the process.

The agreement does not guarantee the health care subsidies will be extended, as Democrats have demanded for almost six weeks. Senate Democratic leader Chuck Schumer of New York voted against moving ahead with the package, along with all but eight of his Democratic colleagues.

A group of three former governors — New Hampshire Sen. Jeanne Shaheen, New Hampshire Sen. Maggie Hassan and Independent Sen. Angus King of Maine — broke the six-week stalemate on Sunday when they agreed to vote to advance three bipartisan annual spending bills and extend the rest of government funding until late January in exchange for a mid-December vote on extending the health care tax credits.

The agreement also includes a reversal of the mass firings of federal workers by the Trump administration since the shutdown began on Oct. 1 and would ensure that federal workers receive back pay.

Senate Majority Leader John Thune quickly endorsed the deal and called an immediate vote to begin the process of approving it as the shutdown continued to disrupt flights nationwide, threaten food assistance for millions of Americans and leave federal workers without pay.

“The time to act is now,” Thune said.

Shaheen, Hassan and King were among the Senators defending the vote in a briefing on Sunday night.

"This agreement will give Democrats control of the Senate floor for a vote on one of our top legislative priorities, extending the Affordable Care Act premium tax credits. This is important when Republicans control every branch of government," Shaheen said.

Democrat Catherine Cortez Masto of Nevada said Republican cooperation and compromise on the issue cannot be ruled out.

"I expect Republicans to be at the table in the next few weeks. I expect the white House to be at the table. And if they do choose not to come to the table, they can own the disastrous premium increases that will continue to rise," she said.

King also said Republicans could be willing to cooperate.

"But Republicans have already started saying, well, here, you know, if this who did this or did that, maybe we can get there."