Belgian authorities on Friday arrested three additional suspects they say are linked to the deadly bombings in Brussels this week, following police operations in the capital city.

One of the police operations occurred in the Brussels district of Schaerbeek, officials said, which is where a taxi driver picked up three of the suspected bombers before the blasts Tuesday.

The raids began Thursday night.

An unnamed suspect was arrested at a subway station in Schaerbeek, and a backpack he was carrying — believed to possibly contain explosives — was detonated by bomb technicians.