Updated

BMW intends to start serial production of a hydrogen-burning 7-Series executive car within two years, the world's largest premium automaker said on Tuesday.

"We will present such a vehicle to the public in less than two years," a spokesman said, confirming media reports.

BMW had said last year its hydrogen-fueled cars, which emit only water vapor, would make their debut in 2010.

BMW intends to build a few hundred such cars at first. They will be able to switch between burning standard gasoline and hydrogen so that drivers will not be left stranded while the infrastructure to deliver hydrogen is built up.

The space that two fuel tanks take up means only the 7-Series will offer the hydrogen package at first. BMW's long-term goal is to offer hydrogen motors in all its cars.

BMW unveiled the world's fastest hydrogen-powered car at the 2004 Paris auto show.

Dubbed the H2R, it can exceed 300 kilometres (185 miles) per hour and reaches 100 km per hour from a standing start in around six seconds.

While BMW is developing fuel-cell driven cars as well, it says it is concentrating on the combustion engine because the sum total of its features and characteristics offers the largest number of advantages and benefits all in one.