MILAN – MotoGP championship leader Valentino Rossi has extended his contract with Yamaha for two more years until the end of 2010, the Japanese manufacturer said on Saturday.

The 29-year-old seven-times world champion joined Yamaha in 2004 and has won two titles with them, as well as 32 races in the top category.

Yamaha said he would continue to be partnered by Spaniard Jorge Lorenzo in 2009.

'After so many years spent in racing, fortunately with so many victories, I needed a special motivation to take the decision to sign for two more years,' Rossi said in a Yamaha statement.

The announcement was made at the U.S. Grand Prix in Laguna Seca, California.

'I had other opportunities but due to Yamaha's efforts to give me the best bike in the best environment, I have decided to stay with Yamaha for two more years,' he said.

Rossi leads Honda's Spaniard Dani Pedrosa by 16 points in the championship with Australian Casey Stoner third for Ducati, a further four points back.

(Writing by Alan Baldwin in Hockenheim; Editing by Peter Rutherford)