The Belgian interior ministry tightened security around the country over the risk of a possible terror attack. The security alert in mid-December came after police arrested 14 suspected Islamists who allegedly planned to free a Nizar Trabelsi, a Tunisian al-Qaeda sympathizer from jail using weapons and explosives. According to reports, Trabelsi was arrested on September 13th, 2001, in an apartment in Brussels; Trabelsi had been in possession of a cache of chemicals which could have been used to make powerful explosives. The interior ministry said that security had been tightened at busy public places such as the capital’s underground and train stations, markets, shopping districts, as well as airports. The security measures remained in place until January 2nd, 2007.