House Republicans are pushing to amend the "fiscal cliff" deal that just passed in the Senate, but as Rep. Barney Frank told TPM, "if House Republicans amend the Senate bill to include spending cuts, they'll effectively kill the deal.":

"If they do, that'll kill the package," he said after a Democratic caucus meeting.

"I would not predict what these people will try to do because they are in thrall to extremists," Frank said. "But if they amend this I don't know how they think they -- an amendment basically says, our ideology is too rigid and we're not really trying to really [reach a deal]."

Speaker John Boehner's (R-OH) office said his members have expressed "universal concern" with the agreement's lack of spending cuts. Rumors on Capitol Hill are that the House GOP is considering amending the legislation and sending it back to the Senate.

House Democratic leaders demanded an up-or-down vote on the Senate deal on Tuesday afternoon.

Rep. Chris Van Hollen (D-MD) declined to discuss whether a GOP amendment to include spending cuts would threaten the bill.

"Look, the country deserves an up or down vote on the compromise bipartisan bill that passed the Senate," he told TPM. "What we're calling for is an up or down vote. Let democracy work its will. ... Let's just take this step by step."

Here's more from The Hill: Senate-passed 'fiscal cliff' agreement in trouble in House:

The Senate’s New Year’s Eve compromise on the "fiscal cliff" hit major turbulence in the House on Tuesday, and the Republican majority is likely to try to amend the bill and send it back to the Senate, House Republicans said.

House Majority Leader Eric Cantor (R-Va.) told his conference he is flatly opposed to the Senate bill without more spending cuts, members said as they emerged from a nearly two-hour Republican meeting in the Capitol.

According to sources in the room, Cantor said that he did not "support" the Senate-backed bill but stopped short of saying he would vote against it if the House took it up on the floor.

The sizeable objections among House Republicans to the Senate approach risks scuttling the deal worked out by Senate Minority Leader Mitch McConnell (R-Ky.) and Vice President Biden on Monday. That deal passed early Tuesday in the Senate by 89 to 8 votes.

GOP leaders repeated "10 to 15 times" that they would only take up an amendment if 218 House Republicans will vote for the amendment. [...]

GOP leaders plan to reconvene the rank-and-file around 5 p.m. on Tuesday.

Boehner told his conference that he was "shocked" that so many Senate Republicans voted for the bill, but he would not indicate how he felt personally about the direction the House should move in.

"He said he was not in favor of the Senate bill," Jones said of Cantor. "I think the Speaker was as open today as I have ever seen him to the will of what the conference wants." Read on...

And from The Huffington Post: U.S. Fiscal Cliff Deal Leaves House Republicans Angry, Deal In Jeopardy:

A high-stakes, multi-layered game of chicken is underway in the Capitol, as House Republicans grapple with how to handle a fiscal cliff bill sent their way by an overwhelming bipartisan vote, even while it's wildly unpopular within their conference.

A vote that had been scheduled on the bill immediately to follow a conference-wide meeting was postponed indefinitely, reflecting the uncertainty surrounding the process. Republicans emerging from the meeting said that the most likely scenario is that the House will amend the bill to add spending cuts, then send it back to the Senate.

"I'll be shocked if this isn't sent back to the Senate,” said Rep. Spencer Bachus (R-Ala.), leaving the meeting. "I don't think that's out of the realm of possibility," said a senior House GOP aide, confirmed by other high-level aides.

They'll have no difficulty making life uncomfortable for Senate Minority Leader Mitch McConnell (R-Ky.), who they blame for getting them in this mess, said one GOP source close to the situation. "He jammed the House. He's gonna get re-jammed," he said of the possibility the House amends the bill and sends it back to the Senate.

But if House Republicans think they can put the onus back on the Senate by amending the bill, they are wildly mistaken, a Democratic Senate aide involved in the talks said. "They are full of hot air. Not a chance we come back," he said.

Following the GOP meeting, Democratic and Republican leaders conferenced by phone to swap notes, trying to determine who has what votes. Democrats think they can get 140-150 members of their caucus, but are not sure that the GOP side can get enough votes to pass the Senate deal. Neither are the Republican leaders. Democrats don't want to be blamed for going over the cliff, but GOP Tea Partiers may see it as an act of courage to do so.

"It may go back with, as someone said, not a poison pill, just enough to give 'em a little heartburn and get it done," said Rep. Bob Turner (R-N.Y.)

The biggest complaint is the lack of spending cuts. Read on...