A car on fire has been driven at the main terminal building at Glasgow Airport, police have confirmed.
Eyewitnesses have described a Jeep Cherokee being driven at speed towards the building with flames coming out from underneath.
They have also described seeing two Asian men, one of whom was on fire, who had been in the car.
The airport has been evacuated and all flights suspended following the incident at 1515 BST.
A Whitehall spokesman said the incident was not being treated as a national security threat.
One eyewitness said: "I heard the sound of a car's wheels spinning and smoke coming out.
"I saw a Jeep Cherokee apparently as if it was trying to get right through the doors into the terminal building.
"There were flames coming out from underneath then some men appeared from in amongst the flames.
"The police ran over and the people started fighting with the police. I then heard what sounded like an explosion."
Eye-witness Richard Gray told BBC News 24: "A green Jeep was in the middle of the doorway burning.
"There was an Asian guy who was pulled out of the car by two police officers, who he was trying to fight off. They've got him on the ground.
"The car didn't actually explode. There were a few pops and bangs which presumably was the petrol."
Taxi driver Ian Crosby said: "This was no accident. This was a deliberate attack on Glasgow Airport."
The reaction of members of the public was not to help the men in the car, but to restrain them, he told the BBC.
Mr Crosby, who said he served in Northern Ireland, told how he shepherded people away from the scene in case of a secondary explosion or a nail-bomb.
Two men, one of whom was reported to be badly burned, were seen being led away in handcuffs.
All flights are cancelled so if your going to glasgow airport, don't go!