An American trainer working with Saudi Arabia's National Guard was killed on Thursday in a helicopter crash in Riyadh in the course of a routine activity, a statement published by state media said.

The Saudi statement gave the trainer's name as Paul Reedy and did not say whether he was a member of the military or a civilian. The US Embassy in Riyadh did not immediately respond to a request for comment.

A Saudi trainee pilot was injured in the crash at Khashm Alan airport in the east of the Saudi capital, which involved a Boeing AH-6i light helicopter gunship, the statement said.

Investigators were still trying to determine the cause of the incident.