Ben Guerdane. A truck loaded with weapons was also found. The quantity of the armaments, and more significantly the fact that such a quantity could be prepositioned show the scale of the security threat posed by the smuggling networks for which Ben Guerdane is known. In 2014, the World Bank estimated that 20% of the active population of Ben Guerdane worked in informal trade "making it arguably the region’s largest economic sector." adding "it accounts for almost half of its trade with Libya," and "totals at least 1.8 billion TND (or over US$1 billion) in Tunisia." While not all informal trade involves smuggling, trade with Libya under the current circumstances, when conducted without customs and security inspections can not be considered anything but a security threat. Particularly considering that estimates of Tunisians who have left the country to join militant organizations range from 3,000 to 6,000, approximately half of whom are believed to be in Libya. Tunisian security officials believe all three gunmen behind the Bardo and Sousse attacks of 2015 had trained in militant camps outside Sabratha.The Islamic State affiliated, Jund al-Khilafah, claimed responsibility for the Bardo and Sousse attacks, and in November Jund al-Khilafah also claimed to be behind the suicide bombing in Tunis which killed twelve members of Tunisia’s Presidential Guard. Tunisian officials have stated that the explosives used in the Tunis bomb attack were of a ‘similar type’ to explosives seized earlier in 2015 which had been fabricated in Libya. After the Tunis bombing Tunisian officials closed the border with Libya entirely for fifteen days, and the Ras Jedir and Dehiba border crossings were closed yesterday. During previous closures, of which there have been several since 2011, Ben Guerdane has seen protests and even rioting in 2013 over the closures and their impact on trade with Libya, legal and otherwise. Early last month Tunisia announced the completion of a 250 km security barrier from the crossings of Ras Jedir to Dehiba along its border with Libya. The system of trenches, fences and moats is to be supplemented with an advanced electronic surveillance system which is due to be installed with the assistance of U.S. and German military engineers, who will also train the Tunisian military on its use. The U.K. has already deployed trainers to the region to assist Tunisia in securing its border. The Tunisian National Guard released images yesterday of the weapons, munitions and explosives it seized during operation Ben Guerdane on Monday, March 8, 2016 when the first three caches were discovered. They include anti personnel mines, mortars, TNT and other explosive materials, significant quantities of ammunition, kalashnikovs, grenades and rocket propelled grenades (RPGs).