Beijing, Aug 11 (Xinhua) Four employees of the Anglo-Australian mining giant Rio Tinto have been arrested on charges of trade secrets infringement and bribery, according to a statement of China's Supreme People's Procuratorate said Tuesday.

The arrested included Stern Hu, general manager of the company's Shanghai office, who was also in charge of the iron ore business in China, the statement says.

The detentions has strained ties between Australia and China and raised doubts that the company's $10 billon sales in the Asian country could be jeopardised.

Rio is the world's second-largest exporter of iron ore, while China is the world's biggest buyer of iron ore. It is also Australia's second-biggest trading partner, with two-way trade valued at A$68 billion in 2008.