CNN) -- Belgian police Thursday arrested a woman they called an "al-Qaeda living legend" as part of an operation to thwart a terror attack being planned to coincide with an EU summit in Brussels, a Belgian police source told CNN.
The police source said officers "had only 24 hours to act."
The leaders of the European Union's 27 member states are meeting in Brussels Thursday and Friday. It is not clear that the heads of state and government themselves were the target of the planned attack.
The federal prosecutor's office in Belgium identified one of the suspects as Malika El-Aroud, the widow of one of the men who assassinated a key opponent of the Taliban in Afghanistan two days before September 11, 2001.
El-Aroud's late husband was one of two men who killed Ahmed Shah Massoud, a leader of the Northern Alliance, in a suicide mission ordered by Osama Bin Laden.
Belgian police aimed to prevent El-Aroud, whom the police source called an "al-Qaeda living legend," from moving to Afghanistan to play a role in the fight against the coalition forces there, the source said.