House lawmakers are doubting that a vote on an Obamacare repeal bill will happen Thursday night, as the White House tries to hammer out a last-minute deal to get conservatives on board.

House leadership is still aiming to vote on the American Health Care Act on Thursday, which is the seventh anniversary of the signing of Obamacare. But as GOP leaders and the White House work to reach a deal, members are doubtful they will vote Thursday.

Rep. Tom Rooney, R-Fla., said there was a 50-50 chance of a vote coming up Thursday night or early Friday morning. But he said a vote should happen soon.

"I think if we go into next week, I think that will be problematic," Rooney, a member of the House whip team, told reporters.

That was before the conclusion of a meeting between the White House and the conservative House Freedom Caucus, which failed to lead to an agreement on how to reshape the bill.

Still, White House spokesman Sean Spicer said he still believes a House vote would happen Thursday, and some members are still bullish on a Thursday vote, with several caveats.

Rep. Steve Stivers, R-Ohio, another whip team member, said a vote will be held Thursday "if we have the votes."

"There are votes moving in all directions right now," he said. "But some have moved to the 'yes' column in the last 10 to 15 minutes, so we got more work to do."

Meanwhile, the House Rules Committee is in a holding pattern until a deal is finalized. The committee must vote to advance any legislation.

Rules Committee Chairman Pete Sessions, R-Texas, said the committee is on 24-hour standby.

"We are waiting for the negotiation with a number of members and several different sides to come to an agreement to pass the bill," Sessions said.

Sessions was asked whether the rules committee could meet over the weekend.

"It's always a possibility," he said.

Sessions said it was important to "let the American people know what the deal is."

"It doesn't bother me at all that we compromise, it does bother me that we don't explain to the American people what we are saying," he said.

Sessions' comments came as the White House was meeting with House Freedom Caucus leaders on the bill. The conservative caucus has been upset the bill doesn't go far enough in dismantling Obamacare.

Conservatives want the bill to include cutting regulations such as essential health benefits that insurers must cover in any plan that is offered on the individual market. But the conservatives are also seeking further changes, including regulations that insurers cover people with pre-existing conditions.

It is not clear, however, if those changes can make it past Senate rules.

The House hopes to pass the American Health Care Act using an arcane pathway called reconciliation. The bill can be passed in the Senate with a simple 51-vote majority, but must reduce the deficit and only affect spending and budgetary levels.

That is why the insurance regulations weren't included in the bill.

Meanwhile, House Speaker Paul Ryan is aiming to quell moderate uprisings against the bill. More than 10 moderates have said they will oppose the bill, including the leader of the moderate Tuesday Group Rep. Charlie Dent, R-Pa.

Ryan met with members of the Tuesday Group on Wednesday night, but shortly afterward Dent announced his opposition to the bill.