Police detained 14 suspected al-Qaida-linked extremists on Thursday in raids in Brussels and eastern Belgium, including one militant investigators claim might have been plotting a suicide attack. The terror sweep came only hours before a European Union summit brought together the heads of 27 countries in Brussels, though the site of the purported attack was unclear. Nearly 250 police officers raided 16 locations in the capital and one in the eastern city of Liege overnight, confiscating computers, data storage equipment and a pistol. "There was no other choice than to intervene today," federal prosecutor Johan Delmulle told reporters. He said one suspect had recorded what looked like a martyrdom video including a farewell message. "It is clear that we have to take the terror threat seriously," Prime Minister Yves Leterme said as he entered the EU summit building. Delmulle said it was unclear where the attack had been planned. The suspects had traveled to both Pakistan and Afghanistan, and it was possible the suicide bombing might have been drawn up there. Thursday's raids were linked to a similar pre-Christmas sweep last year and Delmulle said the investigation showed at the time "a group of people were in Brussels with the task of committing an attack." Investigators waited a year before moving in - opting to ferret out the entire cell rather a single part. "It is now clear to all that we were dealing with a real risk," the justice and interior ministers said in a statement. "It is more than likely that an attack in Brussels has been prevented." At the time of last year's arrests, authorities tightened security, warning of a heightened threat of attacks despite the arrests. Police stepped up patrols at Brussels airport, subway stations and the downtown Christmas market, which traditionally draws large crowds of holiday shoppers. Leterme told reporters that the investigation justified the extreme security measures that were taken over the past year.