The Japanese round of the MotoGP motorcycle world championship has been postponed because of air travel disruptions caused by Iceland's volcanic eruption.

Officials at the Motegi circuit north of Tokyo said the race, scheduled for April 25, has been postponed and a formal announcement would be made later Monday.

The race, the second of 17 MotoGP events, is expected to be postponed until October. Defending world champion Valentino Rossi of Italy won the season-opening race in Qatar on April 11 and leads the standings with 25 points.

The next race is scheduled for May 2 in Spain.