Washington DC - The Senate took a major step Sunday toward ending the longest government shutdown in US history as it cleared the way for a formal debate on a motion to resume funding to federal agencies.

The Republican-led chamber approved a procedural vote by 60 votes to 40, putting a hard limit on how much longer senators can discuss the legislative measure.

It gave lawmakers a maximum of 30 more hours to conduct debate before voting on the motion, which will only need 50 votes to pass.

It will still need approval from the Republican-controlled House of Representatives before it lands on President Donald Trump's desk – a process which could take days.

But the development represents significant progress toward ending a government shutdown that has dragged on for over 40 days, halted funding to federal programs and disrupted air travel and other essential industries.

The breakthrough came after some Democratic lawmakers agreed to a stopgap deal to fund the government through January, despite the fact that it does not renew health care subsidies vital to tens of millions of Americans that expire at the end of the year.

The bill would, however, ensure a vote on extending those subsidies, while also restore funding for the SNAP food stamp program which helps more than 42 million lower-income Americans pay for groceries.

Many Democrats in the House and beyond the beltway came out in opposition to the deal.

Rep. Alexandria Ocasio-Cortez pointed out that the average monthly SNAP benefit is $177 per beneficiary and the average monthly healthcare benefit under the Affordable Care Act is up to $550 per person.

"People want us to hold the line for a reason. This is not a matter of appealing to a base. It's about people's lives," she wrote on X. "Working people want leaders whose word means something."

Fellow progressive Greg Casar of Texas wrote slammed the move as "capitulation" to Republicans, while California Governor Gavin Newsom called it "Pathetic."

As news of the breakthrough emerged, Trump told reporters when he arrived at the White House after a weekend at his Mar-a-Lago estate in Florida: "It looks like we're getting very close to the shutdown ending."

Democratic Senator Tim Kaine of Virginia was among the eight who joined Republicans to support the measure, saying: "I need a moratorium on the punishing of the federal workforce."

Virginia is home to 300,000 federal workers, and the deal would restore all furloughed employees and reverse reductions-in-force layoffs by the Trump administration.

The bill to keep the government funded at pre-shutdown levels "will protect federal workers from baseless firings, reinstate those who have been wrongfully terminated during the shutdown, and ensure federal workers receive back pay" as required by law, Kaine added.

Fellow Democrat and Senate Minority Leader Chuck Schumer could not be persuaded and voted against the measure, saying that "Republicans have spent the past 10 months dismantling the healthcare system, skyrocketing costs, and making every day harder for American families."

His lukewarm opposition didn't stop California Rep. Ro Khanna from pointing out he was "no longer effective and should be replaced."

Transportation Secretary Sean Duffy said earlier Sunday that if the shutdown continued, the number of flights being cut would multiply – even as Americans gear up to travel for the Thanksgiving holiday later this month.

Duffy warned that US air travel could soon "slow to a trickle," as thousands more flights were canceled or delayed over the weekend.

The number of cancellations had surpassed 3,000, with more than 10,000 delays, by Sunday evening, according to data from tracking platform FlightAware.