As a result, a popular downtown market will close at 6:00 p.m. instead of staying open all night as it did in previous years, and the skating rink next door will close at 8:00 p.m.

Fourteen people were detained last week in a plot to free Trabelsi which involved the use of explosives and other weapons. Trabelsi was convicted in 2003 and sentenced to 10 years in jail for

plotting to drive a car bomb into the cafeteria of a Belgian air force base housing about 100 U.S. military personnel.

He admitted at his trial that he met Osama bin Laden at al-Qaida training camps in Afghanistan and asked to be put on a list of "martyrs" willing to be suicide bombers.

Guy Verhofstadt, the Prime Minister of Belgium, also warned of other possible targets in Belgium; security has been stepped up at the airport and in subway stations as well.