Jules Bianchi is undergoing surgery after suffering a severe head injury following a crash at the Japanese Grand Prix at Suzuka.
The 25-year-old Marussia driver crashed into a recovery vehicle after aquaplaning off the wet track at the same corner as Sauber's Adrian Sutil, who had left the circuit on the previous lap.
Sutil's car was still being removed from the area when Bianchi reached the scene of the accident and he hit the recovery vehicle, with the race being red-flagged shortly afterwards on lap 46.
"The CT scan shows that he has suffered a severe head injury and is currently undergoing surgery," an FIA statement read.
"Following this he will be moved to intensive care where he will be monitored. Mie General Hospital will issue an update as soon as further information becomes available."
The running of the race had been under threat all week as Typhoon Phanfone approached Japan from the Pacific Ocean, and the event had already been red-flagged just two laps in after beginning under safety car conditions.
The race continued after the weather cleared up but the rain began to fall in the closing stages ahead of both Sutil and Bianchi's accidents.
Sutil himself has since suggested the safety car should have been sent out after his initial shunt - with the FIA statement confirming the details of Bianchi's crash.
"On lap 42 Adrian Sutil lost control of his car, spun and hit the tyre barrier outside of turn seven," it read.
"The marshals displayed double-waved yellow flags before the corner to warn drivers of the incident. A recovery vehicle was dispatched in order to lift the car and take it to a place of safety behind the guardrail.
"While this was being done, the driver of car 17, Jules Bianchi, lost control of car, travelled across the run-off area and hit the back of the tractor.
"Once the marshals reported that the driver was injured medical teams were dispatched and the safety car was deployed. These were followed by an extrication team and an ambulance.
"The driver was removed from the car, taken from the circuit medical centre and taken by ambulance to Mie General Hospital."
Sutil, who showed no signs of physical injuries after the race, said he knew Bianchi had hit the tractor with some force.
''The car came out to rescue my car and then it all happened,'' he said.
''With respect to this corner, I think everyone knows this is one of the most tricky corners and when it is getting late and the rain increases, let's say when you have an accident there you should probably think about a safety car.
''It was quite difficult. In the end we got more rain and it was dark so was getting less and less and this corner was a tricky one the whole way through.
''In the end, when it got dark, you couldn't see where the wet patches were and that is why I lost the car and it really surprised me.
''It was the same as what happened to me, he had aquaplaning but just one lap later. It hit him hard. That is all I can say. I was just standing there. We know that it is serious at the moment.''