BRUSSELS -- One person was arrested with the dead terrorists that fired on police in Verviers, while the others were brought into custody from a textile town near the German border and in France at Belgium. The other 12 were seized around Brussels, mostly in the Molenbeek region.
"This group was on the point of carrying out terrorist attacks aiming to kill police officers in the streets and in police stations," state prosecutor Eric Van Der Sypt told reporters at a news conference. They were set to act "in the next hours or days."
Belgian Prime Minister Charles Michel said authorities believed have likely thwarted any imminent attack and urged citizens not to worry.
Belgian officials began their investigation several weeks ago. However, since French terrorists killed 12 at the Paris offices of Charlie Hebdo last week, the raids could have been accelerated, according to a former Belgian counter-terrorism chief.
"Paris may have speeded things up," Andre Jacob told RTBF radio. "Some information that may have been barely 'ripe' has been acted on quicker than planned ... because the threat was real."
Although two of the suspected terrorists were arrested in France, state prosecutors have not discovered any link them Islamic jihadists Cherif and Said Kouachi, who killed 17 people in Paris last week at a Jewish store and satirical newspaper Charlie Hebdo.
Reuters contributed to this report.