Tunisian teachers held a protest vigil on Tuesday demanding heightened security to protect educational establishments nationwide, after a petrol bomb was discovered in an institute this week. The explosive was found in a classroom at a secondary institute in the Beradaa area of Ksour Essef in the central governorate of Mahdia. According to a number of locals, the device consisted of a medium-sized drinks bottle connected to wires, placed near a light switch. Police inspected the area and made investigations before the device was taken to the relevant authorities in Tunis for analysis. Teachers meanwhile demanded an immediate intervention by the Ministry of Education, calling for an extended educational and administrative framework to tighten security and prevent outsiders from entering school premises. Tunisia is currently experiencing a nationwide security clampdown in search of al-Qaeda militants, drug dealers and arms smugglers. On Monday, police discovered another explosive device in a private prayer house attached to the Uqba ibn Nafi in Kairouan. The bomb consisted of a vehicle exhaust pipe, again connected with wires, fuel and an alarm clock timer. Tunisia\'s educational establishment meanwhile faces $400 million \"maintenance\" costs, after attacks on schools following the Arab Spring revolution in the country.