Police confirmed Tuesday morning that an ammonia leak led to the evacuation of the building just before 8am.

Police and fire set up a perimeter around the building early Tuesday morning and were still on site a little after 10.30am.

According to our reporting of this story, police and fire services were on site as of 7.30am. Initially, the grand-ducal police closed Rue Edward Steichen between the Clearstream building and the European Parliament.

Our journalist went to the location to obtain information about the operation at 10.30am. At that point, firefighters and an ambulance were still on site.

As of then, security guards were maintaining the perimeter behind the building which remained closed at 10.30am.

These guards were not able to give us further information, but the grand-ducal police have confirmed that it was not a security exercise.

In 2016 the staff of the European parliament had to be evacuated on the same grounds.