China's auto sales returned to double-digit growth in August, despite the summer being a traditionally slow period, an industry group said Tuesday.

Sales rose 10.3 percent year-on-year to 1.65 million vehicles in August, the China Association of Automobile Manufacturers (CAAM) said in a statement.

China is the world's largest auto market and has become critically important to foreign car companies.

Last month's sales growth marked an improvement from July, when sales rose 9.9 percent on the year.

Automakers in China usually carry out equipment maintenance and send workers on holiday in July and August to avoid the country's hottest weather.

But for passenger vehicles alone, sales rose 11 percent year-on-year to 1.35 million vehicles in August, the group said.

In the first eight months of the year, overall auto sales were up 11.8 percent from the same period last year to 13.95 million vehicles, it added.

China's auto sales rose only 4.3 percent to 19.31 million in 2012, hit by limits on vehicle licence plate numbers imposed by some cities to ease traffic congestion and tackle pollution.

But foreign car makers have continued to expand production in China despite worries over the country's slowing growth and potential overcapacity.

Among foreign automakers, US auto giant General Motors sold 245,799 vehicles in China in August, rising 11.2 percent year-on-year and setting a new record for the month, the company said.

Ford Motor Co., another US auto firm, sold 71,183 units in August, up 46 percent compared to the same month last year, it said.