Belgian police have arrested 14 suspected al-Qaeda members, including a man believed to have been planning a suicide attack.
Federal prosecutor Johan Delmulle said: 'We don't know where the suicide attack was to take place.
'It could have been an operation in Pakistan or Afghanistan, but it can't be ruled out that Belgium or Europe could have been the target.'
The arrests were made as European leaders were gathering in the Belgian capital for a two-day summit.
'The information, linked to the fact that a European summit is getting under way at this moment in Brussels, left us no choice but to take action today,' Mr Demulle said.
A total of 242 police officers carried out raids 16 raids in Brussels and one in the eastern city of Liege.
