(CNN) Talks between Republicans across the political spectrum trying to reach a potential immigration deal that would unite the conference have reached a crossroads — and once again it has to do with citizenship.

Lawmakers left town for a weeklong recess on Thursday without fully resolving the issue, but not before two more Republicans signed a petition that could force the House to vote on an immigration package and that has already brought negotiators to the table to come up with an alternative path.

By Thursday morning, the petition stood just five signatures short of the 218 that will circumvent House Republican leadership entirely and bring the issue straight to the floor.

In the meantime, members and sources familiar with the closed-door negotiations described the skeleton of a deal emerging -- but one that will only proceed if a resolution on citizenship is reached.

Circling a deal

At the moment, Republican leaders -- who have been squeezed by insurrections on either flank of their members -- are trying to find a sweet spot between moderates and conservatives in the GOP conference on what would be a permanent solution for recipients of the Deferred Action for Childhood Arrivals program , which President Donald Trump has ended but whose ultimate fate has been tied up in the court system.

The DACA program protects young undocumented immigrants who came to the US as children and most of whom have never known another home besides the US. Conservatives have long argued that they are opposed to any kind of "special path" to citizenship for DACA recipients, as they put it. The vast majority of DACA recipients have no way to become citizens without procedural hoops like leaving the country for more than a decade in the hopes of being able to apply to get back in. Meanwhile, moderates -- who are just a handful of signatures from forcing a wide-ranging immigration debate next month -- are insistent that DACA recipients can have a path to citizenship eventually.

"For us, a bridge into the legal immigration system for young immigrants brought to the country as children through no fault of their own is non-negotiable, and if some colleagues want to continue insisting on denying that, well, there will be no agreement," said Rep. Carlos Curbelo, a Florida Republican who has been leading the moderate group's efforts on the issue.

Curbelo's partner California Rep. Jeff Denham said the group reached "an agreement in principle" in a Wednesday night meeting with leadership, moderates and conservatives, and Curbelo said there was "a loose framework of an agreement." But, he added, he isn't confident yet as "details tend to destroy agreements."

More signatures

On Thursday, two more moderate Republicans, Reps. Tom Reed of New York and Brian Fitzpatrick of Pennsylvania, became the 22nd and 23rd GOP signatures on the petition to force a vote on a series of immigration bills next month. If Republicans get at least 26 signatures, combined with 192 of 193 Democratic signatures expected, the petition would force the votes, which will likely result in the passage of a bipartisan compromise bill. Only one Democratic House member has said so far that he will not sign the petition.

The momentum for that petition, coupled with a conservative revolt in response that tanked an unrelated GOP bill last week, has in the meantime brought together the meetings between leadership, conservatives and moderates to try to negotiate an alternative series of votes in June. Denham has said he won't allow the final Republicans to put the petition over the edge until those negotiations are no longer fruitful.

Though organizers of the effort express confidence that they have until June 11 to gather the necessary signatures and still force votes that month, some members were growing concerned about an indefinite delay.

"My feeling or expectation was that if it were going to happen, it would happen this week," said Pennsylvania Republican Rep. Ryan Costello, who signed the petition the first day. He noted the GOP conference is slated to have a two-hour meeting on the topic June 7. "Perhaps some people are waiting to have that meeting and then if they don't like what they hear there, then they go up and sign it that day, but I do think that the window is starting to close a little bit."

Citizenship the hurdle

According to sources familiar with the negotiations, the meetings have resulted in a clear crossroads over the path to citizenship. During the meeting Wednesday night, GOP leaders were still trying to gauge whether the House Freedom Caucus would support a plan that would offer a bridge for DACA recipients to apply for green cards. Then, once a DACA recipient had a green card they could eventually apply for citizenship like other immigrants.

Talks are unlikely to move forward substantially before that issue is resolved, and it is unlikely that a final decision will come before lawmakers return from their Memorial Day break, which started Thursday.

"Those pretty big things (on border security and citizenship) have to be agreed to, and then you have to deal with the details," said moderate Florida Rep Mario Diaz-Balart, who is involved in talks but declined to get into details of the negotiations. "I'm not saying what has been agreed to or not, but I'm just saying there are some pretty basic things that have to first be to be agreed to."

Before leaving town, Curbelo met with conservative Freedom Caucus members Reps. Raul Labrador, Mark Meadows and Jim Jordan to continue the talks, but the negotiations remain ongoing.

It's unclear if conservatives will be able to agree on the issue, as they have been steadfast in decrying what they call a "special path" to citizenship for anyone who came to the US illegally.

"Still working it," Meadows said of the status of talks. "There were more meetings before we fly out. It's proceeding well, but nothing definite."

"There's a lot of sticking points, not just one," Labrador said of the status of talks before his meeting with Curbelo.

"Every time we meet, we get a little closer. Sometimes that movement is glacial, so you really have to pay attention to observe it, but there is a way here, there is a way," Curbelo said.

House Speaker Paul Ryan, whose lame duck speakership has been tested by the impasse, would not comment on the ongoing negotiations during a news conference Thursday morning, saying only that conversations were constructive and continuing.

A source familiar with the negotiations described the likelihood of a deal between the three parties the following way: "We are closer than we've ever been, but we don't have any guarantees yet," the person said.