Hillary Clinton apparently kept sending classified information over her personal email after leaving the State Department, according to documents obtained by the Republican National Committee.

The file in question is a May 2013 email Clinton sent from her private account to State Department officials and aides discussing the “123 deal” with the United Arab Emirates.

Much of the message is redacted due to classified information. The markings list the material as “confidential” and say it can only be declassified in 2033.

The email was first reported by The New York Post.

Though the nature of the email exchange is unclear due to the redactions, the “123 deal” referred to a 2009 agreement with the UAE to share material and technology for nuclear energy.

As reported by the Post, the email came from Clinton’s hrod17@clintonemail.com account, and was sent to Deputy Secretary of State William Burns, State Department chief of staff Cheryl Mills, top Clinton aide Huma Abedin and others. It was sent months after Clinton left the department.

A review of the now-Democratic presidential nominee’s emails at State already has found the former secretary of state sent more than 2,100 messages with material now considered classified. But those were during her tenure at the department.

Republicans seized on the latest finding to once again challenge her trustworthiness with the nation’s secrets.  

“Hillary Clinton’s secret server jeopardized our national security and sensitive diplomatic efforts on more than 2,000 occasions, and shockingly, it now appears her reckless conduct continued even after leaving the State Department,” Donald Trump spokesman Jason Miller said in a statement. “Hillary Clinton’s terrible judgment shows she cannot be trusted with our national security.”

Clinton has claimed she never sent material that was classified at the time -- though FBI Director James Comey last month challenged that account, even as his bureau declined to pursue charges over her mishandling of sensitive information. 

Regarding the email turned up in the RNC’s Freedom of Information Act request, Clinton spokesman Nick Merrill said Wednesday that the campaign is investigating.

Meanwhile, the FBI is preparing to release some of the documents from its investigation in a matter of days.

Law enforcement sources told Fox News that FBI and Justice Department officials are in the process of determining what exactly will be released to the public.

Fox News’ Jennifer Griffin contributed to this report.