Tupiza (Bolivia), Jan 6 (IANS): Australia's Toby Price, the defending champion in the motorcycle segment of Dakar Rally, was forced to drop out of this year's competition after suffering an injury in the fourth stage.

Riding for KTM, Price fell off his machine around the 371-km mark of the 521 km stage which started from San Salvador de Jujuy, Argentina, before concluding here on Thursday, reports Efe news agency.

"The reigning champion is out of the race," Dakar 2017 organisers said on Twitter, adding that the rider had been "diagnosed with a fractured left femur".

Price, who finished third in 2015 before his win last year, was among the favorites to prevail in the 2017 race and had overtaken overall leader Joan Barreda by a few seconds at the time of the crash.

The Australian won the second stage, but trailed Barreda by 16:19 at the start of Thursday's ride, which took competitors across a dune-filled landscape to altitudes of around 3,500 meters (11,475 feet).

A top contender in the car competition, Qatar's Nasser Al-Attiyah (Toyota), dropped out of the Dakar Rally at the start of Thursday's state due to the "unrepairable damage" sustained by his car.

The 46-year-old rally driver hit a rock on Wednesday, lost a tire and finished 2:17:38 behind the winner of the third stage, France's Stephane Peterhansel (Peugeot), the defending champion.

Al-Attiyah was 2:14:58 behind the overall leader, France's Sebastien Loeb (Peugeot).