By Laura Jarrett, CNN

(CNN) -- Attorney General Jeff Sessions revealed Thursday that Utah's top federal prosecutor, John Huber, is investigating a cluster of Republican-driven accusations against the FBI and has decided that no second special counsel is needed -- at least for now.

Huber has been looking into allegations that the FBI abused its powers in surveilling a former Trump campaign adviser, and more should have been done to investigate Hillary Clinton's ties to a Russian nuclear energy agency, but his identity had remained a secret.

Senator Orrin Hatch released a statement Thursday in response to the news.

“Attorney General Jeff Sessions revealed today in a letter to Congress that United States Attorney John Huber, Utah’s top federal prosecutor, has been leading the investigation of certain issues related to actions by the Department of Justice in 2016 and 2017. Mr. Huber brings decades of experience to his latest, and now very public, assignment. Most importantly, he brings the independent perspective of an accomplished federal prosecutor who has spent his career far removed from the politics of Washington. Attorney General Sessions has picked the right man for the job. I am confident that Mr. Huber will perform these duties with the utmost integrity, and I look forward to learning the results of his work at the appropriate time.”

But Sessions' decision to stop short of formally appointing a special counsel like Robert Mueller, detailed in a lengthy written response to three Republican chairmen on Capitol Hill, will likely anger those in the GOP who have recently ramped up calls to investigate claims of political bias at the nation's top law enforcement agencies.

Sessions said he will rely on Huber's review to determine if a special counsel is needed.

"We understand that the Department is not above criticism and it can never be that the Department conceals errors when they occur," he wrote.

"I am confident that Mr. Huber's review will include a full, complete and objective evaluation of these matters in a manner that is consistent with the law and facts," Sessions wrote. "I receive regular updates from Mr. Huber and upon the conclusion of his review, will receive his recommendations as to whether any matters not currently under investigation should be opened, whether any matters currently under investigation require further resources, or whether any matters merit the appointment of a special counsel."

It also comes one day after the Justice Department's internal watchdog office confirmed it would review how the FBI obtained a warrant to monitor Trump foreign policy aide Carter Page, as well as the bureau's relationship with Christopher Steele, the author of the Trump dossier.

Huber, who currently serves as the US attorney in Utah, may now find himself thrust into the middle of a fierce partisan struggle -- with Republicans arguing anything short of a special counsel is insufficient because the Justice Department cannot investigate its own people, and Democrats maintaining that any allegations of bias are an unfounded ploy to distract from Mueller's investigation into possible coordination between Trump campaign associates and Russian officials.

Originally appointed by President Barack Obama in 2015, Huber, along with many other US attorneys, resigned after President Donald Trump took office early last year, but was reappointed by Trump shortly thereafter.

From Uranium One to claims of FISA abuse

For months, Sessions has tried to straddle the line between adhering to the high bar set forth in Justice Department regulations for appointing a special counsel in "extraordinary cases" on the one hand -- and the persistent demands for one raised by some vocal Republicans, including members of the President's legal team, on the other. His own involvement in any decision is further complicated by the fact that he is recused from all investigations related to the 2016 presidential campaign. It was Deputy Attorney General Rod Rosenstein who decided to appoint Mueller, not Sessions.

House Republicans nevertheless first urged Sessions to appoint a special counsel last year to investigate various matters surrounding Hillary Clinton, including how the FBI dealt with her handling of classified information, as well as allegations that a Russian energy nuclear agency donated to the Clinton Foundation in order to later secure her approval of its purchase of a uranium mining company when Clinton was secretary of state.

The deal had to be approved by the Committee on Foreign Investment in the United States, a committee that includes representatives from several US government agencies, including the State Department, which was led by Clinton at the time. The allegations are unproven, and Democrats and Clinton say the allegations are false and an attempt to distract from the Russia investigation.

Fox News host Sean Hannity has devoted considerable coverage to, as he calls it, the Uranium One "scandal," and Trump has scolded reporters for purportedly failing to highlight it as the "real Russia story."

Sessions in November managed to deflect from making a decision on whether to formally appoint a special counsel by saying he had directed "senior federal prosecutors" to examine the Clinton-related issues, who would then "make recommendations as to whether any matters not currently under investigation should be opened" and "whether any matters merit the appointment of a special counsel." He later referred to an unnamed "person outside of Washington" with "many years in the Department of Justice" who was examining the allegations.

But a steady cascade of revelations this year have intensified the GOP pressure on Sessions to act -- including news that top FBI officials involved in the Clinton private email server probe and Russia investigation exchanged text messages disparaging Trump, as well as that a Justice Department official failed to disclose his contacts with the former British intelligence officer who assembled the controversial dossier on Trump and Russia, and finally, that a House Intelligence Committee memo that alleged the FBI failed to adequately inform the judge who approved a surveillance warrant on Page relied, in part, on opposition research funded in part by the Democratic National Committee and Clinton's campaign.

"We do not believe the Department of Justice is capable of investigating and evaluating these fact patterns in a fashion likely to garner public confidence," House Judiciary Chairman Bob Goodlatte of Virginia and House Oversight Chairman Trey Gowdy of South Carolina wrote in a letter to Sessions earlier this month. "[T]he public interest requires the appointment of a special counsel."

In response, Sessions tapped Inspector General Michael Horowitz to look at whether the FBI properly handled applications for surveillance orders under the Foreign Intelligence Surveillance Act -- but that response did little to satisfy Trump and Republican lawmakers, who pointed to the limited scope of the inspector general's authority.

After Horowitz confirmed his own investigation Wednesday, Republicans remained stalwart that a special counsel was still necessary, citing limits on the inspector general's power.

"For instance, the IG's office does not have authority to compel witness interviews, including from past employees, so its investigation will be limited in scope in comparison to a Special Counsel investigation," Goodlatte said in a statement.

"All Americans deserve to know if the rules were followed and whether justice was indeed blind," added South Carolina Republican Lindsey Graham.

This story is breaking and will be updated.