"On Tuesday, we only had personnel necessary for the insurance of security and safety at sights. We only had a minimum occupancy at all sights. It was only on Tuesday. From Wednesday, It is all back to normal," Ine Wenmaekers said.
News emerged earlier on Thursday that Khalid and Ibrahim Bakraoui, two of the three identified suicide bombers in the attacks, initially targeted Belgian nuclear plants but opted to attack public transport after the arrest of a Paris attacks suspect.
Brothers Bakraoui and a third suicide bomber identified as Najim Laachraoui killed at least 31 people and wounded 300 in coordinated attacks on Brussels Airport in Zaventem and a subway carriage near EU institutions at Maelbeek station.
An active manhunt is underway for a fourth suspect believed to have planted a bomb that failed to detonate at the airport.
Belgian Interior Ministry officials pledged earlier in March to protect nuclear power plants from possible terrorist attacks.
