Europe

Belgium remains on high alert after weekend arrests

  • Two Belgian soldiers patrol at Brussels Central train station in Brussels on Sunday, June 19, 2016. The Belgian security level stays at level 3 after the Belgian federal prosecutor's office said early Saturday that homes and car ports were searched in 16 municipalities, mostly in and around Brussels in an anti-terror sweep. (AP Photo/Virginia Mayo)

    Two Belgian soldiers patrol at Brussels Central train station in Brussels on Sunday, June 19, 2016. The Belgian security level stays at level 3 after the Belgian federal prosecutor's office said early Saturday that homes and car ports were searched in 16 municipalities, mostly in and around Brussels in an anti-terror sweep. (AP Photo/Virginia Mayo)  (The Associated Press)

  • Two Belgian soldiers walk by a couple in a cafe as they patrol at Brussels Central train station in Brussels on Sunday, June 19, 2016. The Belgian security level stays at level 3 after the Belgian federal prosecutor's office said early Saturday that homes and car ports were searched in 16 municipalities, mostly in and around Brussels in an anti-terror sweep. (AP Photo/Virginia Mayo)

    Two Belgian soldiers walk by a couple in a cafe as they patrol at Brussels Central train station in Brussels on Sunday, June 19, 2016. The Belgian security level stays at level 3 after the Belgian federal prosecutor's office said early Saturday that homes and car ports were searched in 16 municipalities, mostly in and around Brussels in an anti-terror sweep. (AP Photo/Virginia Mayo)  (The Associated Press)

  • Belgian police help a group of tourists as they patrol in the historic Grand Place in Brussels on Sunday, June 19, 2016. The Belgian security level stays at level 3 after the Belgian federal prosecutor's office said early Saturday that homes and car ports were searched in 16 municipalities, mostly in and around Brussels in an anti-terror sweep. (AP Photo/Virginia Mayo)

    Belgian police help a group of tourists as they patrol in the historic Grand Place in Brussels on Sunday, June 19, 2016. The Belgian security level stays at level 3 after the Belgian federal prosecutor's office said early Saturday that homes and car ports were searched in 16 municipalities, mostly in and around Brussels in an anti-terror sweep. (AP Photo/Virginia Mayo)  (The Associated Press)

Brussels remains on high alert with increased security after a weekend sweep which left three in jail facing terrorism charges.

The MIVB metro system says a half dozen subway stations have reduced entry on request from authorities but all subway lines were running during the morning rush hour Monday.

On Saturday, authorities charged three men with terror-related crimes after weekend raids and the detention of 40 people in a major investigation. Authorities said the probe required "immediate intervention" because they feared a new attack was close.

Prime Minister Charles Michel said the nation would remain "extremely vigilant, hour by hour," and that the terror level across the country would remain at the second-highest level, meaning a threat of an attack "is possible and likely."