Fresh fears of possible attacks being carried out ahead of the 13th anniversary of the 9/11 attacks have strengthened after Libyan terrorists posted pictures of themselves online posing with some of the commercial airplanes they seized from the Tripoli airport last month, The Blaze reported.

In the pictures, soldiers from the group Libyan Dawn can be seen climbing on to the wings of commercial jets while smiling and waving for the camera. These planes could possibly be used to attack across North Africa on the anniversary of the tragedy this month.

After Islamist militants took over the Tripoli International Airport at the end of August, a total of 11 commercial jets from state-owned carriers Libyan Airlines and Afriqiyah Airways were reported to be missing.

Since then, warnings of the deteriorating situation in Libya, which was controlled by dictator Muammar Gaddaffi until he was killed in October 2011, have been on the rise, UK MailOnline reported. "There are a number of commercial airliners in Libya that are missing," one official told the Washington Free-Beacon. "We found out on September 11 what can happen with hijacked planes."

In addition, the timing of the theft has also set off alarms. While September 11 marks the anniversary of the attacks on the World Trade Center, it is also the second anniversary of the raid of the U.S. Ambassador's compound in Benghazi, Libya, which killed four Americans, including U.S. Ambassador Christopher Stevens, according to alleged intelligence reports disseminated within the U.S. government.

When pressed by the Free Beacon, a "senior State Department counterterrorism official" refused to comment on reports of stolen jetliners in Libya. Another State Department told the online publication, "We can't confirm that."

However, Moroccan military expert Abderrahmane Mekkaoui told Al Jazeera television that the planes have been taken by another Islamic group, the Masked Men Brigade. There is "credible intelligence" that the Masked Men Brigade "is plotting to use the planes in attacks on the Maghreb state" on the 9/11 anniversary, he said. 

Sebastian Gorka, a counterterrorism expert, told the Free-Beacon that the planes could be used in two ways to strike North Africa or even as far as the oil fields of Saudi Arabia. 

"The first would be how commercial airliners were used on Sept 11, 2001, literally turning an innocent mode of mass transit into a super-high precision guided missile of immense potency," Gorka, the Maj Gen Charles Horner chair at the Marine Corps University, said.

"The second tactic could be to use the airframe with its civilian markings as a tool of deception to insert a full payload of armed terrorists into a locale that otherwise is always open to commercial carriers," he added.

In the meantime, U.S. officials are reportedly working to track the 11 missing planes.

Since the overthrow of previous dictator Muammar Gaddafi, Libya has descended into turmoil and officials fear it may become another safe haven for terrorists, according to UK MailOnline.