BRUSSELS - Belgium stepped up security on Friday against a possible terrorist attack after arresting 14 suspected Islamic militants and thwarting what it said was a plot to spring an al Qaeda suspect from jail.
"There are indications a terrorist attack could be in preparation," Prime Minister Guy Verhofstadt told a news conference.
Federal prosecutors said the 14 arrested -- suspected members of a militant Islamic group -- had been planning an armed attack to free Nizar Trabelsi, a Tunisian, who was arrested in September 2001 for plotting attacks on U.S. targets.
Authorities increased police patrols at Brussels' international airport, on rail and metro networks in the Belgian capital and at commercial centres during the busy last-minute shopping period before Christmas.
"They were planning to use weapons and explosives to free him ... These means could be employed for another use," Lieve Pellens, spokeswoman for Belgium's federal prosecutors, told a news conference. She added that investigators were not aware of any other specific plan at this stage.
Pellens said Trabelsi was arrested in Belgium for planning to attack U.S. targets.
He subsequently told a radio station he had planned to target a Belgian airbase thought to house U.S. arms.
Belgium hosts NATO, the European Union institutions and the offices of a raft of multinational companies.
