Chuck Grassley. Drew Angerer/Getty Images Republicans have warned President Donald Trump that they would not hold a confirmation hearing this year for any nominee to replace Attorney General Jeff Sessions, who is under fire from the president.

And they shut down the prospect of a recess appointment as well.

Sen. Chuck Grassley of Iowa, the chairman of the Senate Judiciary Committee, which would hold such a hearing, said in a tweet on Wednesday night that there was "no way" it would hold one in 2017.

Grassley said the committee's agenda was set through the year, adding that confirmation hearings for judicial nominees would come first, then those for the sub-Cabinet.

"My agenda is full," he told CNN's Manu Raju on Thursday, adding that his committee wouldn't act on any nominee.

Sen. Lindsey Graham of South Carolina, a member of the Judiciary Committee, told CNN on Thursday that "there will be no confirmation hearing for a new attorney general in 2017."

He said that "there will be holy hell to pay" if Trump were to oust Sessions, adding that it could be "the beginning of the end" of Trump's presidency if he then tried to go after Robert Mueller, the special counsel leading the FBI's Russia investigation.

Multiple Republicans also shut down the idea of a recess appointment, which has gained traction in recent days.

Speaking from the Senate floor, Sen. Ben Sasse of Nebraska, a Judiciary Committee member, said, "If you're thinking of making a recess appointment to push out the attorney general — forget about it.

"The presidency isn't a bull, and this country isn't a china shop," Sasse continued. "Mr. President, you're a public servant in a system of limited government with a duty to uphold and to defend and to teach to our kids the constitutional system of checks and balances. And this, this is the world's greatest experiment in self-government. It works only if all of us, presidents, senators, Republicans, Democrats, independents, and judges — if we all keep our faith to the American institutions and to the rule of law."

And a Republican senator told The Washington Examiner that Senate Republicans were working to ensure Trump could not make any recess appointments, which "have never been an option for Trump."

Concerns about a possible need to replace Sessions have peaked over the past week as Trump has publicly expressed his frustration with the attorney general.

Trump is displeased with Sessions' recusal from all investigations involving the Trump campaign. His recusal allowed Deputy Attorney General Rod Rosenstein to appoint Mueller in May — after Trump abruptly fired FBI Director James Comey — to oversee an investigation into whether members of the campaign colluded with Russian officials to influence the 2016 US election.

On Wednesday, Trump fired off two tweets asking why Sessions had not replaced acting FBI Director Andrew McCabe. And the president on Tuesday morning blasted Sessions on Twitter for having taken what Trump called "a VERY weak position on Hillary Clinton crimes (where are E-mails & DNC server) & Intel leakers!"

The president also asked "where is the investigation A.G." in a tweet in which he discussed "Ukrainian efforts to sabotage Trump campaign."

In an interview with The Wall Street Journal later that day, Trump said he was "very disappointed in Jeff Sessions," a statement he repeated hours later in a Rose Garden press conference alongside Lebanese Prime Minister Saad Hariri.

Trump has not, however, said publicly whether he plans to oust Sessions.

But The Washington Post reported Wednesday night that the president had discussed the possibility of pushing Sessions out and appointing a new attorney general during the Senate's August recess, but that Trump was warned not to make such a move because of the likely fallout.

Democrats and Republicans alike were quick to shoot down the notion of such an appointment, saying they would not allow it to occur.

Normally, any nominee would have to face Senate confirmation, a process that would be extremely difficult to pass, even as Republicans control the Senate. Trump's public comments could make it looks as though he dismissed Sessions to select an attorney general who would be willing to fire Mueller.

If Trump were able to appoint an attorney general while the Senate was in recess, that person could serve — without being confirmed — until the end of the next Senate session, in early 2019.

Already, however, senators are "planning to continue procedural moves to prevent the Senate from formally adjourning for recess," seeking to prevent Trump from making any recess appointment, CNN reported Tuesday.