Eight people have been hospitalized after a strange smell was detected at Sweden’s security headquarters in Stockholm.

The incident occurred on Monday morning when employees working at the Swedish Security Service headquarters reported feeling unwell after being exposed to an unknown substance.

Emergency services were called to the scene and eight individuals were taken to hospital for treatment. The cause of the smell and the nature of the substance are currently unknown.

The Swedish Security Service has confirmed that an investigation is underway to determine the source of the smell and ensure the safety of its employees.

Authorities have also stated that there is no indication at this time that the incident is related to any criminal activity.