Considered the jewel in the Scottish city’s architectural crown, the building had been under restoration after being badly damaged in a 2014 blaze.
LONDON — A large fire has ripped through the Glasgow School of Art in Scotland, officials said Saturday morning, causing extensive damage to a building considered the jewel in the city’s architectural crown.
It was the second time in four years that a blaze has hit the world-famous and beloved building, which was under restoration after a fire that badly damaged it in May 2014.
The building, widely rated as the masterpiece of the Glasgow-born architect Charles Rennie Mackintosh and completed in 1909, was hit by the latest fire overnight Friday.
Peter Heath of the Scottish Fire and Rescue Service told reporters that the call had come in at 11:19 p.m., sending more than 120 firefighters and 20 fire engines to the site.
Mr. Heath said people should be prepared for what they would see after the blaze had been put out: “The damage to this building, regrettably, is very extensive.”
Earlier on Friday, some students graduated from the school. Others later stood on the street in shock as they watched firefighters battle the blaze, the BBC said.
There were no immediate reports of casualties, and the cause of the fire was not immediately clear.
Footage shared on social media showed flames and smoke billowing from the roof. Mr. Heath told reporters that the blaze had “consumed” about 50 percent of the building and had spread to adjacent buildings, including a cinema and shops, which suffered some damage.
Deputy Chief Officer Iain Bushell, in charge at the scene, said, “We would urge the occupants of surrounding buildings to remain indoors and keep their windows closed,” according to The Associated Press.
The leader of the Scottish government, First Minister Nicola Sturgeon, said on Twitter that she was heartbroken: “My first thoughts tonight are for the safety of people — but my heart also breaks for Glasgow’s beloved @GSofA.”
Scotland has deep emotional ties to the building. “In such an iconic building, which has such affection not just for the people of Scotland but for people around the world, any damage in the building has a devastating effect,” Mr. Heath of the fire service said.
The Art Nouveau building, which housed a working art school, was considered a work of art in its own right. It was best known for its library — a multitiered gem, with distinctive fin-de-siècle chandelier lighting; carefully wrought colored balustrades; elongated windows; and ornamental carvings on tables.
The 2014 fire started below the library, when an overhead projector ignited solvent in a student’s artwork, and destroyed much of the interior’s western half.
As restoration work began, the art school’s director, Prof. Tom Inns, said that the 2014 fire had proved to be “a significant catalyst in how we think about the space.”
Celebrities like the actors Brad Pitt and Peter Capaldi were among those who signed up as trustees to help the Glasgow School of Art raise £20 million toward the restoration. Mr. Pitt’s interest in architecture is well known; and Mr. Capaldi, of “Doctor Who” fame, studied at the school in the 1980s. He recorded a tribute to the art students whose works were either damaged or destroyed during the 2014 blaze.
The building had been scheduled to reopen around spring next year, an official told the BBC.
“Devastated that a major fire has broken out at the Glasgow School of Art tonight,” the shadow minister for Scotland, Paul Sweeney, tweeted, calling the Mackintosh “the most architecturally important building in Glasgow.”
A number of roads around the art school were closed while crews tackled the blaze.
Connor Neil, a 22-year-old chef from Glasgow, said residents were being evacuated from their homes and there was a “big orange light” coming from the school that could be seen from streets away, The A. P. said.
The building had attracted around 25,000 visitors each year before the 2014 blaze, with tours conducted by current students at the art school.
