Updated

The momentum that helped carry the massive immigration overhaul through the Senate last month is beginning to fade, as House Republicans slam the brakes on the debate while rejecting the Senate's bill entirely.

The discontent in the House Republican caucus was evident in a closed-door meeting late Wednesday. Cheers erupted when GOP leaders said they would not take up the Senate-passed bill.

"One thing is clear. House Republicans want to do this on our terms and not on the Senate's terms and not on the president's terms," said Rep. Michael McCaul, R-Texas, chairman of the House Homeland Security Committee.

Senate leaders, who had been banking on the assumption that political pressures would force the House to act, are now watching as the House weighs options that would be a direct challenge to those who crafted the original bill.

Sens. John McCain, R-Ariz., and Charles Schumer, D-N.Y., who helped write the Senate bill, still voiced optimism after emerging Thursday from a meeting with President Obama and Vice President Biden.

McCain said his message to House colleagues is "we are ready to negotiate" and stressed that the two chambers can find "common ground."

House Speaker John Boehner also said "Republicans ought to be part of the solution."

But the House is taking a very different approach. Boehner and other GOP leaders said Wednesday they will take a "step-by-step" approach -- meaning they will break the legislation into a series of smaller bills.

And that's if rank-and-file Republicans will agree to vote on anything. Sources told Fox News that Republicans repeatedly voiced concern Wednesday about border security. But they raised another concern that could signal major problems ahead -- that if the House passes anything, the proposal would then go to what is known as a conference committee, where select lawmakers from each chamber would try and hammer out a compromise. The concern is that the conference committee could produce a bill that House Republicans can't abide.

Rep. Kevin Cramer, R-N.D., said the members are fearful and don't "trust the conference process."

Sources told Fox News that Boehner repeatedly stood up during the meeting to tell members he would not appoint any House members to a conference committee who don't reflect the position of the chamber.

"But they're not hearing that," groused one Republican member. "It just goes over their head."

White House Press Secretary Jay Carney on Wednesday said the administration knew this would be an "uphill battle."

"Hard things are hard," he said.

Fox News' Chad Pergram contributed to this report.