Republican legislators said there would be no vote Thursday night on House Speaker John Boehner's plan to end the U.S. debt crisis because of a lack of support within their own party.

The vote was aiming to raise the nation's debt limit by $900 billion and lay out future savings.

But an aide to House Democratic chief Nancy Pelosi reported that the GOP had delayed the vote out of concerns that they couldn't firm up enough support among their ranks.

The vote was initially set to occur between 5:45 p.m. and 6:15 p.m. Thursday, but that time was pushed back as Boehner tried to wrangle up enough votes to secure passage.

Earlier in the evening, Republicans halted debate on the bill and Boehner asked that several party members meet behind closed doors at his office.

When asked what was happening in the office beyond the glare of the Washington media, GOP Rep. Jeff Flake told The Associated Press "I think that's rather obvious … There's negotiations going on."

Flake had been among those summoned to his office. But despite intense, last-minute negotiations, the Republicans remained deadlocked within their own party, even before the potential bill faced opposition Democrats.

Senate Democrats have unanimously said they oppose the newly modified plan, which also faces the likelihood of a White House veto.

Boehner drafted the plan, which would cut about US$917 billion in future spending over the next 10 years, largely through putting limits on budgets for various departments.

As a trade-off for the spending cut commitments, Boehner's plan would allow the U.S. debt ceiling to be temporarily raised by approximately $900 billion -- or enough to cover America's debts for the next six months.

He said on Wednesday that his plan isn't perfect, but it's the best way forward for the government as it bears down on the looming Aug. 2 deadline to increase its borrowing ceiling.

Boehner said it's "the best opportunity we have to hold the president's feet to the fire. He wants a $2.4 trillion blank cheque that lets him continue his spending binge through the next election. This is the time to say no."

But some GOP members feel the plan doesn't go far enough to cut down on spending.

According to earlier public statements, it speared that a handful of holdouts were from the South Carolina and affiliated with tea party groups.

Some rookie conservatives visited a chapel near the Capitol Rotunda as the deadlock continued.

When asked if he was looking for divine wisdom in the chapel, Rep. Tim Scott, R-S.C., said he was already sure.

"I was leaning no and now I am a no," he told the AP.

As the Republicans squared off among their own, Obama's White House appeared to taunt them.

"Clock ticks towards August 2, House is naming post offices, while leaders twist arms for a pointless vote. No wonder people hate Washington," said White House Communications Director Dan Pfeiffer in a tweet.