(CBS NEWS) -- A House committee says a State Department officer told panel members there were 13 threats made against the U.S. consulate in Benghazi, Libya during the six months before the Sept. 11 attack on the facility.
The assault left four Americans dead, including Ambassador Christopher Stevens.
The panel adds that the officer told it the U.S. mission had made repeated requests for increased security.
A spokesman for the House Oversight and Government Reform Committee, which is holding a hearing on the controversy next week, says its source is Regional Security Officer Eric Nordstrom, who was stationed in Libya from September 2011 to June 2012.
According to the panel, Nordstrom has already given a private briefing to members and will be called to testify at the session next Wednesday.
Separately, The Washington Post says one of its reporters found "sensitive documents" that were "only loosely secured" in the burned-out remains of the consulate Wednesday. The newspaper says the discovery "further complicates efforts by the Obama administration to respond to what has rapidly become a major foreign-policy issue just weeks before the election."
The oversight committee has also requested testimony from a second State Department official, Deputy Assistant Secretary for International Programs Charlene Lamb, who is involved in reviewing security requests.
Republicans have accused the Obama administration of being unprepared for the terrorist attack by Muslim extremists on the consulate, then allegedly issuing misinformation about it.
Initially, U.S. United Nations Ambassador Susan Rice suggested the attack was spontaneous, sparked by an anti-Islam video on the Web.
Secretary of State Hillary Clinton has said she's committed to finding out exactly what happened leading up to the assault and whether security requests were made but denied.
"No one wants the answers more than we do here at the (State) Department," Clinton said. It has appointed a review board to investigate the controversy.
A letter to Clinton from the committee chairman, Darrell Issa (R, Calif.) and panel member Rep. Jason Chaffetz (R, Utah) had said the information came from "individuals with direct knowledge of events in Libya."