The New York Times reported that the Obama administration secretly approved arms shipments to Libyan rebels from Qatar last year, but later learned that the weapons were being turned over to Libya's Islamist militant fighters. According to the Times:
The United States, which had only small numbers of C.I.A. officers in Libya during the tumult of the rebellion, provided little oversight of the arms shipments. Within weeks of endorsing Qatar’s plan to send weapons there in spring 2011, the White House began receiving reports that they were going to Islamic militant groups. They were “more antidemocratic, more hard-line, closer to an extreme version of Islam” than the main rebel alliance in Libya, said a former Defense Department official.
More than a year after the overthrow of Gaddafi, Libyan authorities have failed to establish full control over Libya’s disparate armed factions. According to the Times, "The weapons and money from Qatar strengthened militant groups in Libya, allowing them to become a destabilizing force since the fall of the Qaddafi government."
At the time the decision was made to approve shipments from Qatar, a number of U.S. officials assumed that Qatar would not defy U.S. wishes. However, the Times notes that a number of officials were concerned about the scant control the U.S. had over the Qatari shipments -- many of which still cannot be traced.
"The experience in Libya has taken on new urgency as the administration considers whether to play a direct role in arming rebels in Syria, where weapons are flowing in from Qatar and other countries," reported the Times. There is no evidence that the US-sanctioned weapons were used in the Benghazi attack that killed four Americans in September.