Western intelligence agencies have issued a warning that eleven missing airplanes from Libya’s Tripoli International Airport could be used in terrorist attacks ahead of the 9/11 anniversary.

After Islamist militias identifying themselves as Libyan Dawn took control of the airport last month, aircraft from the state-owned Libyan Airlines and Afriqiyah Airways were found to be missing. During the past two weeks, intelligence reports were distributed within the US Government that spoke about one or more planes being used in a possible attack on the anniversary of 9/11 later this month.

"We found out on 11 September what can happen with hijacked planes."

The Washington Free Beacon quoted a US official as saying: "There are a number of commercial airliners in Libya that are missing. We found out on 11 September what can happen with hijacked planes."

Officials were further quoted as saying that US intelligence agencies have not confirmed the theft following the takeover of Tripoli International Airport and were trying to locate the missing aircraft, as security in the country continues to deteriorate amid fighting between Islamists and anti-Islamist militias.

The missing aircraft raises an additional serious counter-terrorism concern, as 9/11 also marks the second anniversary of the Libyan terrorist attack on the US diplomatic compound in Benghazi, which killed four US citizens.

The Metro UK newspaper reported that the intelligence reports presented another scenario, where a plane with civilian markings could be used to transport armed terrorists to an airport.