Belgium detained 14 people yesterday suspected of links with Al Qaeda, including one who may have been planning a suicide attack, federal prosecutors said.

"We do not know where this suicide attack was to take place. It could have concerned an operation in Pakistan or Afghanistan, but it is not excluded that Belgium or Europe could have been the target," prosecutors said in a statement.

"The criminal investigation concerns people suspected of taking part in the activities of a terrorist group, namely Al Qaeda," it said.

Prosecutors said authorities had been forced to act yesterday because 27 EU heads of state had started a summit in the Belgian capital. Police raided 16 properties in Brussels and one in the eastern city of Liege, seizing computers and documents but no weapons or explosives.

The detained suspects were due to appear in court later yesterday, a spokesman for the prosecutor's office said. She declined to give further details, including their nationalities.

Prosecutors said their investigation had concerned suspects who had travelled to Afghanistan or Pakistan to take part in fighting or training.

The statement referred to four Belgians who had travelled there at the end of last year, three of whom had since returned. Two had been back for a few months, another more important figure arrived in Belgium on December 4.

"In any case it appears from recent information in the investigation that this third person was possibly planning to carry out a suicide attack," the statement said.

The suspect had received clearance to carry out this operation from which he would not return.