The school's Mackintosh building has been completely devoured by the flame, but no casualty has been reported so far.

The blaze started at around 11 pm on Friday and spread through nearby buildings.

Reports said that neighbouring Campus nightclub and O2 ABC music venue have suffered significant damages.

According to Deputy Chief Officer Iain Bushell, more than 120 firefighters have been deployed to douse the flame.

The Mackintosh building, which was destroyed in a fire incident four years ago, was due to open next year, following restoration.

Reacting to the news, Glasgow North East MP Paul Sweeney said in a tweet that he is devastated.

In a series of tweets, he said, "Devastated that a major fire has broken out at the Glasgow School of Art tonight. The Mack has been undergoing restoration since the last devastating fire in 2014. @scotfire_glasgo are doing everything they can to salvage the most architecturally important building in Glasgow."

"The Mack restoration project, led by @pagepark and others, has been an incredibly innovative effort to restore Mackintosh’s masterpiece to life. I can only hope that the skills developed on it since 2014 will help to overcome this horrific setback. We cannot lose this building.

"The 2014 fire destroyed around 20% of the western wing of the building - a later extension completed in 1909, containing the spectacular library - with a further 30% smoke damaged. This fire appears to be much more extensive and affects the 1899 eastern wing of the building.

"A major reason the 2014 Glasgow School of Art fire spread so rapidly was because of the horizontal and vertical timber-lined air ducts that run through the building. I wouldn't be surprised if the same ducts have exacerbated the rapid and comprehensive spread of the fire tonight," the MP added.

Hailing the courage of firefighters, Scottish First Minister Nicola Sturgeon tweeted, "Once again, we are indebted to the bravery of our firefighters and other emergency services. This is clearly an extremely serious situation. My first thoughts tonight are for the safety of people - but my heart also breaks for Glasgow’s beloved @GSofA."

Image: twitter.com/fire_scot