Internal State Department emails reviewed by Fox News reveal that as security unraveled in Yemen, U.S. personnel were scrambling to finalize their exit plan and were so uncertain about what would happen that procedures for safeguarding sensitive information were bypassed -- with permission from Washington. 

The unclassified emails reveal staff on the ground in Yemen, as well as senior department executives in Washington, were concerned the evacuation might go bad and left a communication network running at the embassy in case staff had to return. The emails point to uncertainty on the ground amid fast-moving developments, even as the Obama administration downplayed any irregularities. 

"It wasn't hasty," State Department spokeswoman Jen Psaki insisted on Fox News' "The Kelly File" on Feb. 12, a day after the evacuation. 

But one email reviewed by Fox News showed genuine concern -- even panic -- in Washington, that an unclassified system exposing emails and day-to-day operations was left up and running at the embassy in Sanaa. 

"We need to quickly think about the plan for destroying/sanitizing the OpenNet data that is still in Sanaa," the email from a supervisor said. 

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"I am a little worried it is still out there." 

That referred to a main communication link with Washington, known as OpenNet. The emails show that system -- at what was one of the most heavily guarded U.S. embassies in the Middle East -- was not shut down, in what was described to Fox News as a break in standard practice. 

On Feb. 8, Ambassador Matthew Tueller -- with the approval of Under Secretary Patrick Kennedy, one of the State Department's most senior executives -- ordered staff to leave the OpenNet link up, in case the evacuation plan failed and they had to return to the embassy for an indefinite period. 

But the worried email sent three days later showed the ramifications of leaving the system exposed, and it urged officials to implement a plan to destroy or clean up that data "as soon as possible." 

The U.S. joined Britain and France last week in pulling out of Yemen, closing their embassies and removing staff amid a civil war driven by Iran-aligned Shiite rebels. Yemen is also home to one of the most dangerous Al Qaeda affiliates, and the U.S. pullout has raised questions about the future of the U.S. counterterrorism program there. 

But the fact that sensitive information was left at the compound raises additional questions. 

Fox News is told that after the U.S. team fled, it took three days to remotely access and delete the remaining data. Servers containing financial information, as well as passport and visa requests with personal information, also had to be cleared. 

Tony Shaffer, a former military intelligence officer now with the London Center for Policy Research, explained how the information left unguarded at the compound could have posed problems. 

"If they are able to exploit it, that is say break it open and potentially analyze it and categorize it this will give them a great deal of information about how U.S. embassies function," he said. 

Psaki, speaking with Fox News, acknowledged that not everything went as planned. 

But, she said, "We've been planning these for weeks and everybody was following the proper protocol put in place for the advance." 

Psaki's claim that there was a long-standing plan conflicts with email traffic, just days before the evacuation, requesting further guidance and instruction on closing the embassy. 

Also, by Feb. 8, three days before the evacuation, the emails clearly show the plan was to leave on commercial air, and not a U.S. military aircraft, which would have allowed the Marines at the post to take their weapons with them. During the evacuation, military personnel had to destroy or render inoperable their weapons before boarding the aircraft. There is no evidence the State Department tried to charter out to a U.S.-controlled airbase that would have allowed the Marines to stay armed. 

Asked about the emails on Wednesday, Psaki said: "We successfully moved our personnel out. And I think that's what everybody should be focused on."

Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security. Herridge joined FNC in 1996 as a London-based correspondent.