Islamist militias in Libya took control of 11 commercial planes last month, and Western intelligence agencies issued a warning that the jets could be used in terrorist attacks on the anniversary of the 9/11 terrorist hits on the United States.

International media report that intelligence of the stolen jetliners were distributed within the US government and included a warning that one or more of the aircraft could be used in an attack on the anniversary of the 11 September, 2001, terrorist attacks against New York and Washington.

 “There are a number of commercial airliners in Libya that are missing,” said one official. “We found out on Sept. 11 what can happen with hijacked planes.”

The reports also come three weeks before the second anniversary of the terrorist attack on the U.S. diplomatic compound in Benghazi that killed four Americans, including Ambassador J. Christopher Stevens.

A senior State Department counterterrorism official declined to comment on reports of the stolen jetliners. A second State department official sought to downplay the reports. “We can’t confirm that,” he said.