Officials are investigating what caused an Amazon cargo plane to overshoot the runway after landing at Miami International Airport in a deadly incident on Sunday.

Five people were killed and five others seriously injured when the plane, which was operated by 21 Air, crashed just before 14:00 (18:00 GMT). None of the group have yet been identified.

The plane, a Boeing 767-300, crossed a road beyond the runway and hit several vehicles on the ground. It is not yet clear whether those who died were in the aircraft, on the ground, or both.

21 Air, a charter company based in North Carolina, said it was "devastated by the accident involving one of our aircraft in Miami".

Both 21 Air and Amazon said they were co-operating with the investigation.

"At least five people have lost their lives, and five others are injured," Miami-Dade County Mayor Daniella Levine Cava said at a news conference on Sunday evening.

She added that rescue crews arrived at the scene within "seconds" of the crash.

Three of the five people injured were in critical condition, Miami Fire Chief Raied Jadallah said.

Several of the injured were trapped inside or under vehicles on the ground, and needed to be extricated by fire and rescue crews, Jadallah added.

Over 200 firefighters responded after the plane burst into flames.

Officials say it is too early to know the cause of the crash, which is being investigated by the National Transportation Safety Board (NTSB).

The federal agency, which investigates all air crashes in the US, plans to hold a news conference of its own on Monday.

Experts who spoke to the Associated Press news agency said video footage of the plane's landing would present investigators with the question of whether or not the aircraft touched down within its designated zone on the runway - and if so, what happened.

All flights at the airport were temporarily grounded by the Federal Aviation Administration (FAA). The incident came over Labor Day weekend, one of the busiest travel times of the year.