The Gherkin building in London, UK, was eacuated on Thursday as emergency services were called to investigate the alarm.
The London Fire Brigade confirmed the alarm in the building stating 30 St Mary Axe has been evacuated.
Staff in nearby offices were told that fire crews had been called to reports of smoke in the building's basement and that workers had been evacuated as "protocol".
London Fire Brigade has tweeted that the fire crew will be leaving the Gherkin building shortly. The twitter handle said that there was no fire but a fuse in a basement room had burnt out.
Many people took to Twitter to post the images of London Fire Brigade trucks outside the building, wishing that there was nothing serious. Officials have become cautious after Wednesday's terror attack outside UK Parliament which killed 5 people and injured over 20.
More details on the incident are awaited.