Vettel out before the start in Bahrain

Sebastian Vettel's hopes of fighting champions Mercedes for victory in Sunday's Bahrain Formula One Grand Prix went up in smoke before the start when his Ferrari's engine blew on the formation lap.

The German, who had finished third in the Australian season-opener two weeks earlier, parked up between turns 13 and 14 at the Sakhir circuit with a plume of smoke trailing out of the rear of his car.

Four times world champion Vettel and team mate Kimi Raikkonen had qualified third and fourth respectively behind the Mercedes of triple champion Lewis Hamilton and championship leader Nico Rosberg.

"I don't know yet," Vettel told Sky Sports television when asked what the problem was. "I lost power, saw smoke coming out and we decided to stop. Why? I don't know at this stage.

"It's obviously frustrating...whether the engine has damage or not we'll see. I don't think it's the same thing as Kimi's in Australia."

Raikkonen retired in Australia with flames flickering from the airbox of his car.

With McLaren's Fernando Alonso not starting after failing a medical following his big crash in Australia, and team mate Jenson Button retiring on lap seven, there were more world champions watching the race from the sidelines than in it.