President Joe Biden gave the strongest sign yet on Friday night that the drama in Washington might be drawing to an end -- saying an agreement was "very close."

Talks ran into the early hours of Saturday, but Democrats reportedly drew a red line at Republican demands for tougher work requirements in exchange for social aid that they say would kill party support for a deal.

Briefing reporters on Capitol Hill Saturday morning, Republican congressional leader Kevin McCarthy acknowledged negotiators "are not there yet" -- but said he was confident of meeting the critical June 5 deadline for a deal.

That is the day when, short of an accord allowing it to keep borrowing, the US government says it will run out of money to pay its bills -- raising the prospect of a default that would likely trigger a recession and send shockwaves through the global economy.

"Yes," the House speaker said without hesitation, "I feel we can get there, I really do. I am an optimist."

"I feel closer to an agreement now than I did a long time before," McCarthy said, adding: "Some things we just have to finish out."

The dreaded June 5 deadline is four days later than a previous X-date, but still guarantees that -- even with a deal this weekend -- it will be a frantic race to get a bill through Congress in less than 10 days.

Negotiators were hoping to settle on a text Saturday afternoon, but winning bipartisan support for its adoption will test the skills of party whips, with grumblings already on both sides over the concessions being made.

The deal believed to be taking shape would include an agreement to extend the government's borrowing authority for two years, meaning no repeat of the current drama before the 2024 presidential election.

But Democrats would have to offer some ground on Republican demands for sweeping spending limits on social safety and other domestic programs -- most controversially a demand that those applying for benefits like food assistance work for them.

Hostage-taking accusation

The White House has pushed back hard, accusing Republicans of putting at risk "over eight million jobs unless they can take food out of the mouths of hungry Americans."

McCarthy earlier set the tone for the final-stretch negotiations by reposting a clip of himself telling reporters:

"I do not think it's right that you borrow money from China to pay people to stay home that are able bodied with no dependents on the couch.

"That is not the American way. That is not what we believe."

Members of Congress left for a 10-day recess at the start of the long Memorial Day weekend -- with Biden himself, to the consternation of some in his own party, spending the weekend at his Camp David retreat, then his home in Delaware.

Economists have spent months raising the prospect of economic catastrophe should the government default, but both the White House and Republican leadership insist they are negotiating in good faith and are confident a deal will be reached in time.

McCarthy has said lawmakers would have 72 hours to review any text before a vote, and will get 24 hours' notice if they are required to return to Washington for a vote.

The debt ceiling raise is an annual accounting maneuver that usually passes with little notice. It simply allows the government to keep borrowing money to pay for bills already incurred through the budget.

This year, the increasingly hard-right Republican Party has decided to turn the debt ceiling into leverage to force Biden to roll back favorite Democratic spending priorities.

Republicans call this taking responsibility for the $31 trillion national debt. The White House accuses the opposition party, which controls the House of Representatives, of taking the economy hostage.

The Treasury Department said its cash balance fell on Thursday to $38.8 billion -- which observers noted was less than the net worth of several dozen of the world's wealthiest people, including Elon Musk, Jeff Bezos and Bill Gates.