Firefighters are currently attending an incident at a town centre office building.
Two crews have been sent to Sussex House in North Street, Horsham, after a ‘strong smell of burning’ was coming from the building.
An eyewitness said they saw more than a dozen people had been evacuated and were in the building’s car park.
The fire service said the alarm system went off at about 1.20pm.
When crews arrived a ‘strong smell’ of burning - believed to be caused by an electrical fire - was coming from the building.
Firefighters remain on the scene and are continuing to investigate.