UPDATE 1-Mazda China car sales plunge amid tensions over islands

* Sign that island row taking its toll on sales for Japan automakers

* Other Japan automakers have not released Sept figures yet * Nissan and Toyota are cutting back production

(Adds details, background)

BEIJING, Oct 4 (Reuters) - Mazda Motor Corp said on Thursday sales in China for September tumbled 35 percent, one of the first signs that sales from Japanese automakers there are likely to weaken sharply on a row over islands claimed by both nations.

Violent protests broke out across China in late September after the Japanese government bought two of the islands, known as the Diaoyu in Chinese and the Senkaku in Japanese, from their private owners.

Nissan Motor Co and Toyota Motor Corp are cutting back production in China, an unusual move in a market where most automakers had been adding capacity until recently.

Mazda which operates a three-way car venture in China with Ford Motor Co and Chongqing Changan Automobile Co Ltd , said it sold 13,258 cars in China in September.

In the first nine months of the year, its sales fell 6 percent from a year ago to 148,116 cars, it said.

Mazda's large rivals, such as Toyota, Honda Motor Co Ltd

and Nissan have yet to release their September car sales for China.

(Reporting by Fang Yan in BEIJING and Fayen Wong in SHANGHAI; Editing by Richard Pullin and Edwina Gibbs)

((yan.fang@thomsonreuters.com)(86 10 6627 1233)(Reuters Messaging: yan.fang.reuters.com@reuters.net))

Keywords: CHINA CARS/