At least 15 fire trucks were called to a location in the central London district of Knightsbridge on Wednesday, the London Fire Brigade confirmed. Footage of the affected area on William Street showed plumes of smoke billowing into the sky.

The fire has reportedly affected the 5-star Mandarin Oriental Hyde Park hotel and at least 120 firefighters had been deployed to the scene.

The Fire Brigade said the blaze was "producing a lot of smoke" and was "very visible," its cause "is not known at this stage." Police added that the hotel, which has 198 rooms, was being evacuated.

Roads were closed off at Scotch Corner and Hyde Park Corner, busy junctions near the hotel, causing traffic chaos during rush hour.

The hotel is a 12-story Edwardian-style building that was made in 1902 and opened its doors as the Mandarin Oriental in 1996.

A hotel spokesman confirmed that they were aware of the fire, but "as the situation is still unfolding, we have no further details to share at this time, but will provide an update soon."

Later, the authorities said they were still assessing the situation but thus far had no reports of injuries. While the cause of the fire has not been publically confirmed, witnesses described seeing smoke near the site where workers were repairing the 116-year-old building's roof.

es/kms (AFP, dpa, Reuters)