The incident occurred shortly before 10am, when smoke was seen coming from an establishment located on the rooftop.
Emergency services were quickly dispatched to the scene, with fire crews currently on site handling the situation.
At this stage, the cause of the smoke remains unclear and no further details have been confirmed. It is also not yet known whether anyone has been injured.
A larger fire brigade was deployed and a security perimeter was set up.
At around 10.20am, the all-clear was given. The operation was brought to an end, the perimeter was lifted and people were allowed back into the building.