Updated

London Fire Brigade says about 100 firefighters are tackling a blaze at a luxury hotel.

Video footage shows smoke billowing from the roof of the Mandarin Oriental Hotel in London's ritzy Knightsbridge area.

The fire brigade says it was called just before 4 p.m. (1500 GMT) to the 12-story hotel. It says 15 fire engines and 97 firefighters are at the scene.

Smoke from the fire can be seen for miles. The major road in front of the hotel has been closed, causing rush-hour traffic chaos in that part of London.

The cause of the fire is not yet known.