The attack in Benghazi, Libya, that killed US ambassador Christopher Stevens and three other Americans has dealt the Central Intelligence Agency a setback in its intelligence-gathering efforts at a time of increasing instability in the North African nation.
Among the more than two dozen American personnel evacuated from the city after the assault on the American mission and a nearby annex were about a dozen CIA operatives and contractors, who played a crucial role in conducting surveillance and collecting information on an array of armed militant groups in and around the city.
"It's a catastrophic intelligence loss," said one US official who has served in Libya and who spoke on the condition of anonymity because the FBI is still investigating the attack.
"We got our eyes poked out."
The CIA's surveillance targets in Benghazi and eastern Libya include Ansar al-Sharia, a militia that some have blamed for the attack, as well as suspected members of al Qaeda's affiliate in North Africa, known as al Qaeda in the Islamic Maghreb.
American intelligence operatives also assisted state department contractors and Libyan officials in tracking shoulder-fired missiles taken from the former arsenals of Gadhafi's forces; they aided in efforts to secure Libya's chemical weapons stockpiles; and they helped train Libya's new intelligence service, officials said.
Senior US officials acknowledged the intelligence setback but insisted that information was still being collected using a variety of informants on the ground, systems that intercept electronic communications like cellphone conversations, and satellite imagery.
The state department and the White House declined to comment on the matter.