At the renowned Somerset House in London, some 125 firefighters are fighting a fire.

The historic arts center, which is situated on the Thames River, is often bustling with visitors on weekends and features pieces of art by artists including Vincent van Gogh.

However, firefighters are fighting to contain a fire that is reportedly in a "small part of the building" as it spreads.

Social media posts and videos depict a section of the roof on fire, with smoke rising over the Thames, prompting worries for some of the artwork within.

Twenty fire engines, according to London Fire Brigade, were on the scene attempting to contain the fire on the building's roof.

"The brigade's control officers have taken over 10 calls reporting the fire, with the first received at 11.59am," said a statement.

"Crews from Soho, Dowgate, Islington and surrounding fire stations are attending the scene."

The brigade said the cause of the fire is currently unknown.

Somerset House was due to host a day of breakdancing on Saturday but has since been closed during the emergency response, and all staff and members of the public are said to be safe.

In a statement, Somerset House said: "Somerset House is currently closed due to a fire which has broken out in one small part of the building.

"All staff and public are safe and the site is closed.

"The London Fire Brigade arrived swiftly and we're working very closely with them to control the spread of the fire."

Somerset House was once a royal palace and is now an arts, culture and entertainment centre.

The Courtauld Gallery, home to one of the world's great art collections, is located in the building's North Wing and contains works by the likes of Vincent van Gogh.

Alan Robinson, 71, a Catholic priest who works nearby and lives in Covent Garden, said he was worried about the "irreplaceable" art collection in the Courtauld Gallery.

The Somerset House site dates back to 1547.
Michelle Birkby, 50, who lives in London, said: "I was walking along the South Bank, and could smell smoke, looked up and saw smoke coming out of the top of Somerset House.

"At first I assumed it was a barbecue in the courtyard, or some sort of event, but then I heard the fire engines, realised the smoke was billowing out of control and that Somerset House was on fire."

She added: "It's a place I visit quite often and I know it's beautiful and I really hope they can stop the fire before it does too much damage."

The director of Somerset House Trust said the fire broke out in the west wing of the building, where there are "no artworks in that area".

Jonathan Reekie, 59, said the fire was spotted around midday and the site was immediately evacuated.

The fire is concentrated in an area that is "mainly offices and back-of-house facilities," he added, as it appeared firefighters had begun to get the blaze under control.