WASHINGTON (Reuters) – A senior Republican congressman on Friday asked the U.S. State Department inspector general to investigate why part of a 2013 public briefing that dealt with Iran nuclear talks was cut from a video before it was posted online.

The excised portion of the Dec. 2, 2013, briefing included a question about whether an earlier spokeswoman for the department had misled reporters about whether the United States was holding secret direct nuclear talks with Iran.

“In tampering with this video, the (State Department) Bureau of Public Affairs has undermined its mission to ‘communicate timely and accurate information with the goal of furthering U.S. foreign policy’,” House Foreign Affairs Committee Chairman Ed Royce said in a letter to the inspector general, Steve Linick.

“This is all the more troubling given that the video in question dealt with hugely consequential nuclear negotiations with the Islamic Republic of Iran,” Royce added in the letter, released by his office.

The State Department initially said it believed a “glitch” caused the gap but on Wednesday said an internal inquiry found it was a deliberate omission. However, it said no rules were broken because none existed governing the integrity of the briefing transcript and video. Rules are now being put in place.

On Thursday, a department spokesman said that the inquiry, carried out by the department’s Office of the Legal Adviser, had run into a dead end.

On Friday, a U.S. official who spoke on condition of anonymity said the department cannot use internal phone records to trace who requested the cut to the 2013 briefing video because it keeps such data for only 24 hours.

Separately, another congressional Republican, House Oversight and Government Reform Committee Chairman Jason Chaffetz, on Tuesday wrote to Secretary of State John Kerry asking for documents related to the edited video.

(Reporting by Arshad Mohammed; Editing by James Dalgleish)