Two people have died and two have been seriously injured after a private jet sped off runway in South Carolina airport and crashed into a fence.

The private jet landed at 1.40pm on Thursday at the Greenville Downtown Airport, but instead of coming to a stop it ran off the runway and crashed into a fence, breaking the aircraft into two.

The Greenville Police Department says there were four people on board, three men and one woman. Two were pilots and the two passengers were a married couple.

Greenville City Fire spokesman Tristan Johnson confirmed that the two people who died in the crash were the pilot and the co-pilot of the plane, according to WSPA.

The passengers are in the hospital in critical condition. The victims are yet to be named.

Police spokesman Donnie Porter announced after the crash:

For some reason, we’re not sure why, [the plane] was not able to stop, went off the end of the runway, and crossed to the grass on the runway, that’s about another 200 feet, then down an embankment and finally came to rest at the airport road.

I believe that one of the pilots, not sure which, was either temporarily unconscious or what not but was leaning on the throttle.

Police spokesman Porter said that this was the biggest accident the airport has seen in a long time.

By Thursday evening the FAA was en route to take over the investigation.