Senate Republicans are delaying a vote on the chamber's health care bill until after lawmakers' July 4 recess, as GOP efforts to overhaul the Affordable Care Act teeter on the brink of collapse.

Senate Majority Leader Mitch McConnell, R-Ky., said discussions on the measure would continue toward “getting at least 50 people in a comfortable place.”

“We’re going to continue the discussions within our conference on the differences that we have, that we’ll continue to try to litigate,” he told reporters after a lengthy meeting with the Senate GOP conference.

Asked if the delay meant the bill was dead, McConnell said, “No, no.”

“This is a very complicated subject,” he said. “Legislation of this complexity almost always takes longer than anybody else would hope. But we’re going to press on. ... We’re optimistic we’re going to get to a result that’s better than the status quo.”

McConnell said the entire Republican conference has been invited to the White House to plot their next moves in a confab expected to occur Tuesday afternoon.

Democrats, meanwhile, said efforts to defeat Republican moves to repeal the Affordable Care Act, also known as Obamacare, likely are not over.

“The Republicans cannot excise the rotten core at the center of their health care bill, no matter what tweaks they may add in the next week and a half,” Minority Leader Chuck Schumer, D-N.Y., told reporters. "If our Republican colleagues stick to this base bill ... we're going to fight the bill tooth and nail, and we have a darn good chance of defeating it – a week from now, a month from now, a year from now."

The delay came after Sen. Mike Lee of Utah became the fifth Republican to signal he would not vote to approve moving forward with debate of the bill, formally called the Better Care Reconciliation Act. GOP leaders had hoped to take that step as early as Tuesday, and to hold a floor vote on the bill by Friday.

"We have always said we won't vote to proceed on a bill we can't support," said Conn Carroll, a spokesman for Lee, who had not ruled out voting for the final version of the bill if some changes are made.

Lee's announcement followed the release of a Congressional Budget Office report Monday that projected the Senate proposal would increase the number of uninsured people by 22 million over roughly the next decade. He joined Sens. Susan Collins of Maine, Dean Heller of Nevada, Rand Paul of Kentucky and Ron Johnson of Wisconsin, who all announced or strongly signaled that they would vote to block the motion to proceed, in effect killing the bill's progress.

Sen. Ted Cruz of Texas last week joined Paul, Johnson and Lee in saying he opposed the bill as it was originally written, but all four left the door open at the time to supporting an adjusted proposal. Others, including Sens. Marco Rubio of Florida and Shelley Moore Capito of West Virginia, appear undecided.

"We continue to have productive discussions," Cruz said Tuesday after meeting with McConnell.

Paul, for his part, met with President Donald Trump on Tuesday to discuss his concerns with the bill. The president has backed the measure and has made calls to senators, as McConnell can only afford for two of his 52-member caucus to vote against the bill.

Trump "is open to making [the] bill better," Paul said after the meeting. "Is Senate leadership?"

Republicans' vow to repeal and replace the Affordable Care Act has become a political albatross for McConnell and other GOP leaders who are eager to move to other priority items on their agenda.

The conundrum they face is is particularly difficult: Polling has showed a GOP health care overhaul already passed by the House is unpopular among the broader public – and less popular than Obamacare – but a measurable chunk of Republicans' own likely voters say they would punish lawmakers at the ballot box if they fail to repeal the existing law.

And even if the Senate manages to pass its measure, some are skeptical the conservative wing of the Republican caucus in the House – where leaders struggled to push their bill through – will accept it.