From 21 to 25 November 2015, the government of Belgium imposed a security lockdown on Brussels, including the closure of shops, schools, public transportation, due to information about potential terrorist attacks in the wake of the series of coordinated terrorist attacks in Paris by Islamic State of Iraq and the Levant on 13 November. One of the perpetrators of the attack, Belgian-born French national Salah Abdeslam, was thought to be hiding in the city. As a result of warnings of a serious and imminent threat, the terror alert level was raised to the highest level (four) across the Brussels metropolitan area, and people were advised not to congregate publicly, effectively putting the city under lockdown.