A huge fireball engulfed a bus in Stockholm city centre after it crashed into the entrance to a tunnel this morning.
The vehicle was travelling towards a height restricted bridge when it crashed into warning barriers hanging from the top.
As the bus struck the heavy pontoons, it is thought the gas tank on the roof was pierced and caused an explosion.
The vehicle, which was thought to have not been in service at the time, became engulfed in flame, sending thick black smoke billowing into the air.
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The bus was engulfed in a fireball after colliding with the warning barriers on a height restricted bridge in the centre of Stockholm today
Smoke was sent billowing after a bus exploded and caught fire on Klarat in central Stockholm
Emergency services were called at around 11.25am local time and rushed to the scene at the Klarat tunnel in the middle of busy Stockholm city centre.
The driver was injured and believed to be the only person on-board at the time.
He was taken to hospital as police closed off the area, sources told Swedish newspaper, Aftonbladet.
Björn Wallentin, who lives near the explosion, told the paper: ‘I thought it was a terrorist attack.
‘I heard a big bang first and then several smaller ones. It seemed like a scaffolding collapsed.’
Photos and video footage from the scene show the bus in flames and thick black smoke.
Thick black smoke was sent flying through the air along the Stockholm skyline after the bus crash this morning
Emergency services battled to stop the fireball spreading from the burning bus to nearby buildings
Witnesses described seeing black smoke rising from the site of the accident.
Others believed scaffolding had fallen down after the huge bang was heard ringing out.
Andrei Picus, who was in a car behind the bus moments before the explosion, said the vehicle smashed into the entrance of a tunnel.
He tweeted: ‘The explosion in Stockholm was caused by a bus hitting the top of the entrance to a tunnel.
Only the driver of the bus was thought to be on-board at the time of the accident. The driver was rushed to hospital
‘The gas tank which was above exploded on impact. We were in the car next to them. The bus was empty. They hit the height warning device behind them but didn’t notice.’
According to Asa Sköld, management operator at the emergency serviceshe gas tank on the roof has exploded, local media reported.
Just under 40 minutes after the explosion, the emergency services still fought against the flames, it was reported.
Mr Sköld told local media firefighters extinguished the flames and tried to protect nearby buildings.