Updated

A review of threats made against embattled Environmental Protection Secretary Scott Pruitt challenges claims his office made to justify spending millions of dollars on extra security and first-class travel, according to documents released Tuesday.

The confidential security assessments at the EPA show no evidence of specific, credible or physical threats against Pruitt despite claims that there was an “unprecedented” number of death threats made against him.

Democrats on the Senate Environment and Public Works Committee wrote in a letter Tuesday that they have reviewed security assessments describing that is 16 purported threats against Pruitt, which include public protests, criticism of Pruitt's policies and other activities protected by the First Amendment.

The letter from Sens. Tom Carper of Delaware and Sheldon Whitehouse of Rhode Island urged the committee's Republican majority to begin oversight hearings into Pruitt's unusual security precautions.

Committee Chairman John Barrasso quickly rebuffed that request, saying no hearing on Pruitt's security procedures will be held. The Wyoming Republican lashed out at his Democratic colleagues, accusing Carper and Whitehouse of improperly disclosing "law enforcement sensitive information" without the approval of EPA or the Secret Service.

Pruitt has come under scrutiny over the past several weeks for questionable spending at the EPA. He defended his decision to take a $50 a day condo rental from the wife of a lobbyist. He also pushed back on allegations he helped facilitate big raises for two of his closest advisers after the White House refused to sign off on them. He’s also come under fire for reportedly spending $3 million on security, including overtime pay and round-the-clock armed officers hired to protect him.

Last week, EPA spokesman Jahan Wilcox said last week there had been an "unprecedented" amount of death threats against Pruitt and his family. Wilcox doubled down on that assertion Tuesday, but did not immediately respond to a request from AP to release details of the specific incidents to which he was referring.

President Trump, meanwhile, has publicly supported Pruitt.

In a tweet on Saturday, Trump suggested Pruitt had been the victim of multiple death threats.

"While Security spending was somewhat more than his predecessor, Scott Pruitt has received death threats because of his bold actions at EPA," Trump tweeted. "Record clean Air & Water while saving USA Billions of Dollars. Rent was about market rate, travel expenses OK. Scott is doing a great job!"

The Democrats said they found no records describing specific, credible threats against Pruitt. An internal EPA document recounted such threat as attempts by protesters to disrupt a speech and a post card sent to Pruitt that said: "CLIMATE CHANGE IS REAL!!! We are watching you."

The Democrats also obtained a Feb. 14 assessment from EPA's Office of Homeland Security Intelligence that concluded "EPA Intelligence has not identified any specific, credible, direct threat to the EPA administrator."

The internal review said an earlier threat assessment by Pruitt's security team "does not employ sound analysis or articulate relevant `threat specific' information appropriate to draw any resource or level of threat conclusions regarding the protection posture for the administrator."

The AP reported that Pruitt's concern with his safety came at a steep cost to taxpayers as his swollen security detail blew through overtime budgets and at times diverted officers away from investigating environmental crimes. Pruitt's 20-member full-time detail is more than three times the size of his predecessor's part-time security contingent.

EPA's inspector general is currently auditing Pruitt's security spending -- one of at least five ongoing probes by the agency's watchdog into spending and ethics issues surrounding the administrator.

Shortly after arriving in Washington, Pruitt, 49, demoted the career staff member heading his security detail and replaced him with EPA Senior Special Agent Pasquale "Nino" Perrotta, a former Secret Service agent who operates a private security company. Perrotta oversaw a rapid expansion of the EPA chief's security detail to accommodate guarding him day and night, even on family vacations and when Pruitt was home in Oklahoma.

Perrotta also signed off on new procedures that let Pruitt fly first-class on commercial airliners, with the security chief typically sitting next to him with other security staff farther back in the plane. Pruitt's premium status gave him and his security chief access to VIP airport lounges.

Pruitt has said his use of first-class airfare was initiated following unpleasant interactions with other travelers. In one incident, someone yelled profanity as he walked through the airport.

A nationwide search of state and federal court records by AP found no case where anyone has been arrested or charged with making violent threats against Pruitt.

In November, BuzzFeed News investigative reporter Jason Leopold filed a public records request with EPA for copies of government records about death threats to Pruitt. Leopold told AP this week that an EPA official who responded to his request told him verbally that after checks with the agency's general counsel and inspector general's office that no such records existed.

The Associated Press contributed to this report.