Schumacher explains his retirement - 4th April 19:42pm GMT

Michael Schumacher has ruled out track debris as the cause of his retirement from Sunday's Bahrain Grand Prix.

The seven times world champion made clear on his website on Monday that the problem was with Ferrari's new F2005 Formula One car, which failed to score points on a troubled debut at the Sakhir circuit.

"At first I thought that it (the damage) may have happened due to all the small parts of debris flying around in the first lap," said Schumacher. "But that was not the reason for the hydraulic problem, as we found out when we performed our checks."

Schumacher's retirement was his first in three and a half years due to a mechanical failure and his explanation will increase concern about the new car's fragility.

Brazilian team mate Rubens Barrichello struggled with gearbox problems all weekend and also needed an engine replacement on Sunday.

"Of course we have to improve the reliability," said Schumacher. "But we have shown in the past that we are very good at doing that."

The German, winner of the first five races of last year, has just two points after the first three of 2005 in the worst season's start of his career.

Renault's Fernando Alonso, winner of the last two races, leads the championship with 26 points.

Schumacher said Ferrari, constructors' champions for the past six year, would be back strongly.

"We mustn't be fooled by the first few races," he said. "The season is very long this time, there are 16 races left so a lot can still happen. As I said, I'm expecting a few wins in the F2005. I haven't given up the fight one bit."