Firefighters were called to an office near Waterloo station after reports of rising black smoke billowing from a building.
London Fire Brigade confirmed it was called to a fire near the station at 1.15pm but has yet to release details of the incident.
According to witnesses, the blaze broke out at The Tower Building in York Road.
London SE1 tweeted: “Fire crews from Old Kent Road, Dowgate, Peckham and Euston dealing with Elizabeth House rooftop fire at Waterloo."
While Leo Lord-Jones wrote: "Multiple fire units lining up outside Waterloo station following reports of a fire at adjacent Tower office block."
Lara Roussel posted a picture of black smoke rising from her office.
She posted: “Our office is on fire!”
London Fire Brigade said the incident was dealt with by 2.20pm.
