PARIS  - The death of South African motorcycle rider Elmer Symons overshadowed the fourth day of the Dakar Rally in Morocco on Tuesday.

While Spain's double world rally champion Carlos Sainz stretched his overall lead in the car category and compatriot Marc Coma took over at the top of the motorcycle standings, earlier events reinforced the rally's deadly reputation.

The race has now claimed 49 lives in its 29-year existence, 24 of them competitors.

Organisers said in a statement on the rally Web site (www.dakar.com) that KTM rider Symons, a 29-year-old resident in the United States, was killed in a crash on the sandy 405km stage between Er Rachidia and Ouarzazate.

He had been taking part in his first Dakar as a competitor, helped by brother Kingsley, after following two previous editions as part of an assistance team.

Symons had been 18th overall in the event, considered one of the most challenging and dangerous in the world of motorsport, which ends in the Senegalese capital on January 21.

The Dakar started in Portugal on Saturday already clouded by safety and security concerns.

Two children were killed by rally vehicles last year and Australian motorcyclist Andy Caldecott died in a separate crash.

The year before, motorcyclists Juan Manuel Perez of Spain and Italy's Fabrizio Meoni were killed while competing.

After Tuesday's stage, Sainz led Volkswagen team mate Giniel de Villiers of South Africa by one minute and 55 seconds with Portugal's Carlos Sousa in third place as competitors confronted their first dunes. France's Jean-Louis Schlesser won the stage.

Champion Luc Alphand of France was sixth overall for Mitsubishi but team mate and multiple winner Stephane Peterhansel lost time with a burnt out clutch.

Defending champion Coma took the overall lead in the motorcycle section from compatriot Isidre Esteve after dominating the and day and is now nearly 12 minutes clear.