At least 12 people have been arrested overnight during anti-terrorist operations across Belgium on suspicion of plotting attacks reports RT, the federal prosecutor said. Reports says that one of the suspects worked at Zaventem Airport and had previously contacted a Brussels suicide bomber.

“In connection with a criminal investigation concerning terrorism… 40 people were taken for questioning. Twelve of them were arrested. The investigating judge will decide on their possible detention later today,” the prosecutor’s office said.

Some 40 addresses were searched during the raid.

The anti-terrorism operation was carried out in 16 areas, according to RTBF. Apart from Brussels, these sites included Molenbeek-St-Jean, Schaerbeek, Anderlecht, Koekelberg, Sint-Agatha-Berchem, Evere, Forest, Watermael-Boitsfort, Ganshoren, Zaventem, Ninove, Wemmel, Fleurus Tubize and Liège.

Evidence was gathered [and] as part of the instruction [we] needed to intervene immediately,” the federal prosecutor said in a statement.

No guns or explosives have been found during the raids so far.

Brussels 12 Terrorist arrested
In Brussels 12 Terrorist arrested

The suspects were planning to carry out attacks in the areas of events linked to Euro-2016 in Brussels this weekend, Flemish-speaking VTM broadcaster reported.

The broadcaster added that the attacks could have been targeted the festive events linked to Saturday’s Euro-2016 match.

One of the suspects arrested Friday evening was reportedly working at Brussels’ Zaventem Airport, local media reported, citing sources. Man who was identified by the media as Youssef E.A, 29, was allegedly a childhood friend of Khalid El Bakraoui, one of the suicide bombers in Brussels’ Maelbeek metro station on March 22.

The man had direct access to the planes, local media said. Police reportedly found messages on his computer allegedly sent to El Bakraoui which state that planes from US, Russia and Israel take off every Tuesday from Zaventem.

Belgium has been on high alert since twin suicide bombings hit Brussels’ Airport and Maelbeek Metro station on March 22. The Metro station was not far from the building housing the EU Commission and the Council of the European Union, as well as NATO headquarters.

With a population of about 11 million people, Belgium has been the source of more Islamic State (IS formerly, ISIS/ISIL) recruits per capita than any other country in Europe, according to the United Nations Working Group.

2 police cars set ablaze in Brussels’ mostly Muslim district of Molenbeek
2 police cars set ablaze in Brussels’ mostly Muslim district of Molenbeek

In June, reports emerged that Belgium’s capital may once again see terror attacks beginning this month, as schools, hospitals and public places where people gather for Euro-2016 related events may be targeted by extremists during the Islamic Ramadan holiday.