An unnamed "senior aide" to Hillary Clinton, who was secretary of state at the time, left behind classified material unsecured and unattended in a hotel room following a trip to China in 2010, according to a new report.

News of the 2010 security mishap, which was first discovered by Fox News, comes as the FBI revisits its investigation into Clinton's use of a private email server during her tenure at the State Department. New documents, which the bureau believes could be pertinent to its probe of Clinton, were unearthed during an investigation into disgraced Rep. Anthony Weiner's sexting scandal. Weiner is the estranged husband of senior Clinton confidante Huma Abedin.

"In May 2010, Secretary Clinton was on official travel in Beijing, China, accompanied by senior staff. Upon Secretary Clinton’s departure, a routine security sweep by Diplomatic Security agents identified classified documents in a staff member’s suite," State Department spokesman John Kirby told Fox News, which issued a Freedom of Information Act on the matter several weeks ago.

Diplomatic Security is tasked with protecting the secretary of state — as well as other high-ranking foreign dignitaries visiting the U.S. — both domestically and internationally. A source with knowledge of the 2010 incident told Fox Diplomatic Security filed the initial report on a Form 117 while the Marine Security Guards filed a separate formal statement on it.

California Rep. Devin Nunes, Republican chairman of the House Permanent Select Committee on Intelligence, asked the FBI Monday for more information after a whistleblower alleged it was Clinton who left the classified information behind.

But Kirby insisted Clinton had no part in the China incident.

"To be clear – this was not Secretary Clinton’s hotel room and no citation whatsoever was given to Secretary Clinton, nor were any reports written about Secretary Clinton’s conduct," he said.

At the time the room was examined, and the classified documents were found, the hotel room was still considered a Diplomatic Security-controlled area, Kirby said, adding there was still a security agent situated right outside the suite.

In a statement, Kirby indicated while information was determined to be "improperly secured," what was found "did not support assigning culpability to any individual" and since the files were picked up while the room was still being guarded, "the likelihood that the information was compromised was remote."

Regardless, leaving classified information unattended is an extremely serious offense.

"Diplomatic Security and the Marine Security Guard takes exposure of classified information very seriously," Jessica Vaughan, director of policy research at the Center for Immigration Studies and a former State Department staffer, told Fox. "You can lose your security clearance if you’re caught more than once, and that means you might lose your job."

"It’s a big deal," she added.

In his letter to the FBI, Nunes also raised concerns about an email obtained as a result of the FOIA request that showed Abedin asking a fellow staffer to remove "burnstuff" she had left in a motorcade vehicle during a trip to India. Kirby, however, said the incident with Abedin involved no classified — but potentially sensitive — information.

"This email exchange does not show that classified information was left in a motorcade car," the State Department spokesman said. "Sensitive But Unclassified material is routinely disposed of in burn bags. As the regulations state, Sensitive But Unclassified (SBU) and Personally Identifiable Information (PII) documents are often burned. So it’s not accurate that any reference to a document going to a burn bag is a document that includes classified material."