Sen. Marco RubioMarco Antonio RubioApple under pressure to unlock Pensacola shooter's phones Senators offer bill to create alternatives to Huawei in 5G tech Surging Sanders draws fresh scrutiny ahead of debate MORE (R-Fla.) plans on briefing Republicans on progress in crafting an immigration reform bill during the next Republican policy luncheon.

Rubio, who has been involved in bipartisan negotiations on crafting an immigration reform bill, said he had been given the green light to update his Republican colleagues next week.

"Earlier this week, I requested and received permission to brief the entire Republican conference during our policy lunch next week. I look forward to briefing you at that meeting," Rubio wrote in a letter to four Senate Republicans on Friday.

Rubio's letter was in response to the four GOP senators, Mike LeeMichael (Mike) Shumway LeeSenators are politicians, not jurors — they should act like it Sens. Kaine, Lee: 'We should not be at war with Iran unless Congress authorizes it' Overnight Defense: War powers fight runs into impeachment | Kaine has 51 votes for Iran resolution | Trump plans to divert .2B from Pentagon to border wall MORE (Utah), Jeff SessionsJefferson (Jeff) Beauregard SessionsICE subpoenas Denver law enforcement: report Bottom Line DOJ inquiry tied to Clinton, touted by Trump winds down with no tangible results: report MORE (Ala.), Chuck GrassleyCharles (Chuck) Ernest GrassleyGOP can beat Democrats after impeachment — but it needs to do this one thing Trump administration planning to crack down on 'birth tourism': report Senate begins preparations for Trump trial MORE (Iowa), and Ted CruzRafael (Ted) Edward CruzJuan Williams: Counting the votes to remove Trump Sunday shows - All eyes on Senate impeachment trial Cruz: Hearing from witnesses could extend Senate trial to up to 8 weeks MORE (Texas), who urged Rubio and other senators involved in the immigration negotiations to offer more transparency on the bill's progress.

The four senators sent a letter to the Republican senators in the so-called bipartisan Gang of Eight, urging them to release more details on their negotiations in crafting the immigration proposal. Members of the bipartisan group have recently said they plan to unveil their immigration reform bill soon.

"It is time for you to discuss the status of your negotiations, disclose what concessions have been made, and provide details to members of the Judiciary Committee as well as the entire Republican Caucus," the senators wrote in the letter, released Friday. "As members of the Judiciary Committee, we believe it is critical that the public and the entire Senate body be given adequate time to read and analyze the contents of any immigration bill put forth by the Majority. Our Committee has had only three hearings in recent months, barely touching on issues involving enforcement, border security or the creation of a temporary worker program."

They said that they were "deeply concerned" with recent statements made by Sen. Charles SchumerCharles (Chuck) Ellis SchumerTrump administration installs plaque marking finish of 100 miles of border wall Sanders defends vote against USMCA: 'Not a single damn mention' of climate change Schumer votes against USMCA, citing climate implications MORE (D-N.Y.) that a basic agreement has been reached by the group on legalizing undocumented workers in the U.S. Schumer is one of eight senators involved in the talks.

"We should not further test the faith of the American people by implementing a major overhaul of the immigration system that prioritizes legalizing law breakers over the long-term needs of the country," their letter stated. 

"In that regard, we are deeply concerned by Senator Schumer’s recent statement that your group has “come to a basic agreement, which is that first, people will be legalized. In other words, not citizens, but they'll be allowed to work, come out of the shadows, travel. Then, we will make sure the border is secure," the GOP senators wrote.

  The senators wanted staffers to brief members of the Republican Committee staff by the end of Monday on the specifics of the immigration reform negotiations.

"Therefore, we ask that your staff be made available to brief Republican Committee staff no later than close of business on Monday, April 8," the senators wrote. "We also request that you personally discuss your group’s proposal with the entire caucus early next week so that all members can raise concerns and questions before the deal is finalized."

Senate Judiciary Committee Chairman Patrick LeahyPatrick Joseph LeahyOvernight Defense: Book says Trump called military leaders 'dopes and babies' | House reinvites Pompeo for Iran hearing | Dems urge Esper to reject border wall funding request Senate Dems urge Esper to oppose shifting Pentagon money to border wall Senate opens Trump impeachment trial MORE (D-Vt.) recently told Rubio that he wanted to move quickly on moving the immigration bill to through his committee once it was unveiled.

"Because the President has failed to lead on this matter, your group has secretly met for months and not consulted with members of the Committee about major changes to our nation’s immigration laws," the senators wrote in the letter. "The time for transparency has come. Given the majority’s rushed timetable, we believe it is time for you to discuss the status of your negotiations, disclose what concessions have been made, and provide details to members of the Judiciary Committee as well as the entire Republican Caucus."  

--This report was updated at 5:10 p.m.