The deadly attack on the U.S. diplomatic compound in Benghazi , Libya , was `` likely preventable '' based on known security shortfalls and prior warnings that the security situation there was deteriorating , the majority of the Senate Intelligence Committee concluded in a report released on Wednesday . Separately , the findings also noted what the FBI had told the panel -- that 15 people cooperating with its investigation had been killed in Benghazi , undercutting the investigation . It was not clear if the killings were related to the probe . Moreover , it said that people linked with various al Qaeda-related groups in North Africa and elsewhere participated in the September 11 , 2012 , attack , but investigators have n't been able to determine whether any one group was in command . The report placed some blame for the outcome on the State Department , saying it should have `` increased its security posture more significantly '' in Libya 's second-largest city because of general warnings that U.S. personnel were at risk . The intelligence community `` provided ample strategic warning '' that Americans and U.S. facilities were in danger , though it did n't offer a single warning that would have predicted the Benghazi attack that killed U.S . Ambassador to Libya Christopher Stevens and three other Americans , the report said . But the findings did n't spare the intelligence community , saying it might have flagged potential threats to the compound had it done more analysis of `` extremist-affiliated social media . '' It also blasted U.S. intelligence for inaccurately reporting -- without `` sufficient intelligence to corroborate it '' -- that a protest might have led to the attack . The report said the intelligence community took too long to correct the erroneous reports , `` which caused confusion and influenced the public statements of policymakers . '' The Obama administration initially believed the armed assault was triggered by outrage over a U.S.-produced anti-Muslim film . It has since classified it as an organized terror attack . Investigators have n't found evidence of pre-planning and suggest at least part of the attack was `` opportunistic . '' That suggests a vulnerability for diplomatic facilities , because attacks can happen with little warning , the report said . Questions around security and intelligence as well as the slow-to-evolve and changing explanation fueled a ferocious response from Republicans in Congress , who have sharply criticized the administration and continue to investigate . New York Times report casts doubt on al Qaeda involvement in Benghazi . A State Department spokeswoman , Marie Harf , said the report largely affirms the findings of an independent review of the Benghazi matter that recommended steps -- since undertaken by the agency -- to improve security at diplomatic facilities worldwide . On the issue of whether the attacks were preventable , Harf noted that `` we have repeatedly said there was no specific threat '' pointing to an attack . `` Obviously , we 've talked at length about the fact that we knew there were extremists and terrorists operating in Libya and in Benghazi . But , again , we had no specific information indicating a threat an attack was coming , '' she said . The Intelligence Committee report follows the release on Monday of previously classified information by the House Armed Services Committee . According to the documents , senior military officials told the panel there were no discussions related to any specific threat in Libya despite general warnings about the possibility of terror attacks around the anniversary of 9/11 . As a result , additional military assets were not deployed to the area . On the investigation , the FBI was quoted in the report as saying the 15 deaths have severely hampered its probe . `` The FBI 's investigation into the individuals responsible for the Benghazi attacks has been hampered by inadequate cooperation and a lack of capacity by foreign governments to hold these perpetrators accountable , making the pursuit of justice for the attacks slow and insufficient , '' the report said . `` As a result , key information gaps remain about the potential foreknowledge and complicity of Libyan militia groups and security forces , the level of pre-planning for the attacks , the perpetrators and their involvement in other terrorist activities and the motivation for the attacks . '' Several Intelligence Committee Republicans issued a separate set of conclusions . Committee Vice Chairman Saxby Chambliss of Georgia , Richard Burr of North Carolina , Marco Rubio of Florida , Tom Coburn of Oklahoma , and Dan Coats of Indiana said failures that led to the attack could be partly related to Obama 's failure , in their words , to establish a clear detention policy for terror suspects that gets the most out of intelligence collection . Instead of sending terror suspects directly to the military facility at Guantanamo Bay , Cuba , the administration has temporarily interrogated suspects on Navy ships , sometimes for weeks at a time , before sending them to the United States for trial . `` President Obama and his administration must end their efforts to close the detention facility at Guantanamo Bay and must develop a clear , cogent policy for the detention and interrogation of suspected terrorists , '' the Senators wrote . GOP Rep : Benghazi not a 'complete cover-up '
The 2012 attack on the U.S. diplomatic facility killed four Americans . It has become a political flashpoint over security preparations , intelligence , response . Senate committee report notes 15 people cooperating with FBI probe were killed . Also , people with al Qaeda-related groups participated in the armed assault .