"So yes, this is a disappointment, a disappointment indeed ... I regret that our efforts were simply not enough this time," McConnell said.

It marks another blow to the sprawling agenda that Republicans hoped to accomplish when President Donald Trump won the White House and the GOP held both chambers of Congress in November.

The measure came after separate pushes to immediately replace the Affordable Care Act or repeal it with a two-year transition period failed amid GOP divisions. McCain was among four senators who held a news conference to denounce the plan on Thursday, saying they wanted assurances that a better plan would come out of a conference committee with the House. McCain was the only one of those senators to oppose the proposal after speaking to House Speaker Paul Ryan.

Senate Republicans released the plan late Thursday just hours before voting on an amendment to take up the bill. The GOP could only afford to lose two votes on the proposal, which many senators suggested they would not even want to see become law .

Three GOP defections — Sens. Susan Collins of Maine, Lisa Murkowski of Alaska and John McCain of Arizona — sank the measure in a 49-51 vote. McCain, who recently returned to the Senate after getting diagnosed with brain cancer, cast his "no" vote to audible gasps on the chamber's floor, according to reporters there.

The Senate blocked the latest Republican attempt to repeal Obamacare in a dramatic floor vote early Friday morning, yet again stalling — for now — the key campaign goal that eludes the GOP six months into the Trump administration.

Trump, for his part, contended that the senators who opposed the plan "let the American people down." He added: "as I said from the beginning, let ObamaCare implode, then deal."

While Trump has previously suggested letting Obamacare "implode," as a candidate and as president he has usually promoted repealing and replacing Obamacare.

The so-called skinny repeal bill, which the GOP titled the Health Care Freedom Act, .

The bill would have led to an estimated 16 million more Americans uninsured by 2026, according to a late Thursday report from the nonpartisan Congressional Budget Office. Premiums in the nongroup market would increase "by roughly 20 percent relative to current law in all years between 2018 and 2026," the CBO estimated.

Following the vote, Senate Minority Leader Chuck Schumer said Democrats "are not celebrating" but are "relieved" for Americans. He urged the Senate to return to regular order and the committee process on legislation, highlighting the speech McCain made with a similar sentiment when he returned to the Senate Tuesday.

"All of us were so inspired by the speech and the life of the senator from Arizona," Schumer said, tearing up. "And he asked us to go back to regular order ... maybe this can be a moment when we start doing that."

When the Senate voted to start debate on Obamacare repeal Tuesday, two Republicans — Collins and Murkowski — opposed the measure. Following a cross-country trip, the 80-year-old McCain, with a scar above his left eye, cast the deciding vote to move forward with debate.

Going into Thursday's votes, Collins and Murkowski were widely considered the most likely Republicans to oppose the plan. Murkowski cast her "no" vote following reported warnings from the Trump administration after her break from the Republicans earlier this week.

McCain's vote early Friday came as more of a surprise.

"I thought it was the right vote," McCain said as he left the Capitol, according to NBC News.

McCain expanded on that in a later statement, saying that skinny repeal would not offer a real replacement that would increase competition and lower health-care costs.

"We must now return to the correct way of legislating and send the bill back to the committee, hold hearings, receive input from both sides of aisle, heed the recommendations of nation's governors, and produce a bill that finally delivers affordable health care for the American people," he said in a statement.

Just before the vote that blocked the skinny repeal, all votes had been cast on a separate Democratic amendment that ended up failing. The vote remained open as several senators moved to talk to both McCain and Murkowski.

Vice President Mike Pence, who was at the Capitol to cast a potential tie-breaking vote, spent considerable time speaking to McCain, according to reporters in the area. The Arizona senator could eventually be seen laughing with Schumer and hugging Sen. Dianne Feinstein, D-Calif.

Trump, who has been frustrated by the pace of Obamacare repeal despite inconsistent engagement on policy, had cheered McCain as a deciding health-care vote earlier this week.

Donald Trump tweet: .@SenJohnMcCain-Thank you for coming to D.C. for such a vital vote. Congrats to all Rep. We can now deliver grt healthcare to all Americans!

It is not clear what actions Congress could take on health care from this point. In his remarks Friday, McConnell said it will be "interesting to see what [Democrats] suggest is the way forward."

Added McConnell: "It's time to move on."