WASHINGTON (AP) -- A State Department official deliberately cut several minutes of videotape from a news briefing dealing with sensitive questions about U.S.-Iranian nuclear negotiations before posting the footage to its website and YouTube, the agency said Wednesday.

In the Dec. 2, 2013, briefing, a reporter asked about the department's denial earlier that year of secret talks between Washington and Tehran. Those discussions had been periodically occurring and eventually led to a breakthrough, seven-nation nuclear deal.

Then-spokeswoman Jen Psaki responded at the briefing: "There are times where diplomacy needs privacy."

But the exchange wasn't on video the department posted on its website and YouTube, even if it remained in the official transcript and backup video for broadcasters. Fox News discovered the discrepancy last month.

On Wednesday, the State Department's current spokesman John Kirby said someone had censored the video intentionally. He said he couldn't find out who was responsible, but described such action as unacceptable.

"Deliberately removing a portion of the video was not and is not in keeping with the State Department's commitment to transparency and public accountability," he told reporters.

Kirby said he learned that on the same day of the 2013 briefing, a video editor received a call from a State Department public affairs official who made "a specific request ... to excise that portion of the briefing." The video editor no longer remembers the name of the person who called, he said.

As a result, "we do not know who made the request to edit the video or why it was made," he told reporters.

While the State Department previously suggested a "glitch" occurred, the sensitivity of the removed portion raised questions.

The reporter, Fox News' James Rosen, started his inquiry by referencing an earlier Feb. 6, 2013, briefing in which State Department spokeswoman Victoria Nuland said no intermittent conversations were occurring between Obama administration and Iranian officials in one-to-one format, outside of larger multilateral gatherings.

Eight months later, those gatherings had become public after reporting by The Associated Press and other media. And Rosen asked Psaki if her predecessor was speaking truthfully.

Upon learning of the video's editing, Kirby said he ordered the original video restored on all platforms and asked the State Department's legal adviser to examine the matter. He said no further investigation will be made, primarily because no rules were in place against such actions.

Kirby said he has ordered new rules created to prevent a recurrence.

By AP