Bentley driver may have suffered 'medical emergency' before crashing $300,000 supercar into Canadian border on ill-fated trip to see KISS with his wife: Authorities struggle to identify couple's 'incinerated' remains after fireball sparked terror fears

A New York businessman who crashed his $300,000 Bentley into the US border with Canada may have had a medical emergency before the smash, it has been claimed.

The 56-year-old, who has not been named, is thought to have suffered some kind of impairment before hitting a barricade at high speed and flying into the crossing.

The driver of the Bentley 'Flying Spur' was seen shooting off the intersection and over an 8ft fence before exploding into a fireball that killed him and his wife.

The pair were said to have just left a casino near the border ahead of a KISS concert in Toronto, which was later canceled when frontman Paul Stanley was taken ill.

The horrifying crash sparked fears of a terror attack on America, but New York Governor Kathy Hochul said late Wednesday it was just a traffic-related incident.

Authorities on the ground were overnight still struggling to confirm the victims' identities from their remains because the wreckage was mostly 'incinerated'.

The couple were intending on driving to a KISS concert in Canada, CNN's John Miller reported, which was later canceled due to a band member suffering from flu.

Miller said there was some speculation the driver, from a well-known family in Grand Isle, New York, had a medical issue.

The dramatic crash closed the Rainbow Bridge on the eve of Thanksgiving - one of the busiest travel days of the year.

Kathy Hochul said on Wednesday night the footage of the fireball was shocking and it was miraculous there were not more injuries.

But she urged calm, saying the two victims were believed to be local people and there was no indication of terrorism.

No explosives were found in the car, according to police sources. One agent with Border Patrol suffered minor injuries in the crash. He was released from hospital.

Asked how they had determined that it was not a terror attack, Hochul said: 'No indication based on online threats or anyone taking credit for this - at this time.

She added: 'It's still unfolding. But I didn't want to leave the public with any uncertainty.

'There is no evidence at this time that there was terror activity.' She said she appreciated the anxiety, and the assumption that it was a terror attack. 

'Based on what is happening in the world, everyone is on edge. This is an international border,' she said.

'I won't call it an accident yet. All we know is there was a horrific incident, a crash, a loss of life - but at this time: no known terrorism activity.'

The FBI Special Agent-in-Charge, Matthew Miraglia, echoed Hochul.

'We do have someone in mind for it and we're working through it through the JTTF,' he said - a reference to the Joint Terrorism Task Force.

'We do not have any derogatory information on this person that we've identified, we're scanning his social media, there's nothing there, we're still running a full investigation so that's a preliminary assessment. 

'We feel, at this point, this might be just something that occurred, there's no larger picture here to look at for now.'

Trini Ross, the US Attorney for the Western District of New York, said their initial investigation determined the incident 'was not terrorism-related' at this stage.

'But we will continue to stay vigilant,' said Ross, saying that people should 'lower their heightened sensitivities knowing that we do not believe this was a terrorist event.' Hochul said she wanted to 'dial back the anxiety'.

'There are still a lot of unanswered questions,' she said. 'But at this time, we just needed to dial down the temperature.

'We are investigating, but at this time there is no sign of terrorist activity.' She said the footage of the crash was 'extraordinary'.

'It's a Western New York resident who was in the city prior to the high speed crash into the median that sent the vehicle airborne,' she said.

'It will leave you in disbelief how it went so high over an eight foot fence. It's quite extraordinary.'

She added: 'The fact that other people and vehicles were not damaged... It was a very congested area. 'Thank God no one else was injured.'

The White House confirmed the president has been briefed on the incident, while Canada's prime minister, Justin Trudeau, said 'additional measures' were being contemplated and activated at border crossings across his country.

Mike Guenther, from Ontario, said he was walking with his wife down Main Street when he saw the vehicle hurtling towards the Canadian border on Wednesday.

He described seeing 'car parts everywhere in pieces' after the horror smash. 'He was swerving as he was going down this road here, fishtailing because he was going so fast,' he said.

'When he hit the fence there was a fire then, but then when he went up again he must have hit the building and there was a big noise and he just shot up in the air and you couldn't see nothing but smoke.

'We heard a big bang. I said there is no way that guy is going to stop, he is just going too fast.

'All of a sudden he went up in the air and then it was a ball of fire like 30-40 feet high, I have never seen anything like it. It was really incredible.'   

Guenther said fire trucks were first on the scene and within 10 minutes there were 'police everywhere'.

'We could see the fireball - that's all we could see, it was just smoke everywhere,' he added. 'I don't think that person is going to survive, their car parts were everywhere.'

He described the car as 'flying' at over 100mph. 'We could hardly even see it was going that quick,' he said.

'There was car in front he swerved around it then it looked like he hit the fence and this fire started.'