WASHINGTON - US Senate Majority Leader Mitch McConnell late Saturday night announced a delay to a vote on a Republican bill to repeal and replace the country's existing healthcare program.

The announcement came after a statement said that Republican Senator John McCain would stay home to recover from surgery on a blood clot, which would leave Republicans short of the votes required to advance the legislation.

The Republican healthcare bill - the Better Care Reconciliation Act (BCRA) - is designed to replace former president Barack Obama's signature healthcare law, the Patient Protection and Affordable Care Act (ACA), also known as Obamacare.

McCain had a 2-inch blood clot removed from above his left eye by surgeons in Phoenix on Friday.

"On the advice of his doctors, Senator McCain will be recovering in Arizona next week," a spokesperson for the 80-year-old senator said in a statement Saturday.

The Mayo Clinic Hospital in Phoenix said "the surgery went very well", and McCain is resting at home "in good condition".

"While John is recovering, the Senate will continue our work on legislative items and nominations, and will defer consideration of the Better Care Act," McConnell said in a statement late Saturday night.

With opposition coming from all Democrats and independents in the Senate, the GOP bill has been on a brink as some Republicans stay undecided.

Two Republicans, Rand Paul and Susan Collins, have made clear that they will vote against the GOP measure.

As Republicans hold a 52-49 majority in the Senate, they could afford losing two votes from their side. And now with McCain staying home, the GOP leadership is less likely to gain 50 votes, a threshold to begin debate on the legislation.

On Sunday, Collins said eight to 10 Republican senators have serious concerns about the legislation.

While Collins said that she did not know if the legislation would ultimately pass, she said as many as 10 Republicans have doubts about it.

"There are about eight to 10 Republican senators who have serious concerns about this bill," Collins told CNN's "State of the Union" program, faulting the bill for its cuts to the Medicaid government health insurance program for the poor, which she said would harm rural hospitals and nursing homes.

"I don't know whether it will pass, but I do know this, we should not be making fundamental changes in a vital safety net program that's been on the books for 50 years - the Medicaid program - without having a single hearing to evaluate what the consequences are going to be," she added.

Paul also reiterated his opposition to the bill, which he described as "terrible" because it retained many of the Obamacare taxes and subsidies.

"The current system is terrible," Paul said on Fox News Sunday. "I don't think Republicans should put their name on this. It is a bad political strategy, and it will not fix the problem."

Xinhua - Reuters