The CIA was transferring surface-to-air missiles from Libya to the rebels in Syria through Turkey when the deadly attack on the US consulate in Benghazi took place, a report says.
As investigation into the death of US ambassador Christopher Stevens and three other Americans last September carries on, the CNN reported on Thursday that dozens of CIA spies were working in an annex near the consulate on a project to supply missiles from Libyan armories to Syrian rebels.
The details of US government activities in Benghazi have since the incident been the issue of controversy with some Congressional leaders pressing for a wide-ranging probe into the attack and the secret operations of the CIA in the African city.
"Since January, some CIA operatives involved in the agency's missions in Libya, have been subjected to frequent, even monthly polygraph examinations, according to a source with deep inside knowledge of the agency's workings," CNN reported.
Sources say more Americans were injured in the attack than what had previously been reported.
The CIA says it has been clear and open about its operations in Bengahzi.
"The CIA has worked closely with its oversight committees to provide them with an extraordinary amount of information related to the attack on US facilities in Benghazi," a CIA statement said.
This is while the CNN says the spy agency has made a huge effort to keep the secrets of its activities in Benghazi from leaking out.
"I think it is a form of a cover-up, and I think it's an attempt to push it under the rug, and I think the American people are feeling the same way," Rep. Frank Wolf said.