Italian motorboat world champion Massimo Rossi has died in an accident during a race on the Moselle river in Germany, police and organisers announced on Sunday.
The 24-year-old was killed when he was thrown out of his boat and hit a tree during a turning manoeuvre.
Italian news agency ANSA quoted the president of the Italian motorboat federation, Vincenzo Iaconianni, as saying that the course was not wide enough and therefore dangerous.
Organisers in Traben-Trarbach have not commented on the allegations.