China has formally arrested and charged four employees of mining firm Rio Tinto with stealing trade secrets and taking bribes¹, Chinese state media reports.

中国国家媒体报道，中国正式逮捕指控了矿业公司里奥廷托四位员工窃取商业机密并受贿。

Rio Tinto workers are accused of spying on China's steel industry

The accused are Australian national Stern Hu and three Chinese employees of the Anglo-Australian company.

The four have been in police custody（监护，拘留） in Shanghai since early July. Rio Tinto denies any wrongdoing.

Australia has urged China to allow Mr Hu - Rio's head of iron ore operations in China - to have access to a lawyer.

"We encourage China to allow Mr Hu all the protections available under Chinese law, including access to legal representation, now that he has been formally arrested," a statement from the foreign affairs department said.

The four employees have been charged with using "improper³ means" to obtain "commercial secrets" about China's steel and iron industry, said Chinese official news agency Xinhua.

However, there was no mention of charges of stealing state secrets, which earlier reports in China had said the four would be accused of, and which carry tougher sentences.

Retaliation⁴ theory

Last month, the Australian trade minister, Simon Crean, warned that business relations with China could be damaged if the case of the detained Rio Tinto workers was not handled appropriately.

Australian opposition⁵ politicians had complained that the arrests might be in retaliation for（报复） the collapse⁶ in June of Rio's proposed deal with Chinese state-owned firm Chinalco.

Rio scrapped⁷ a $19.5bn (£11.8bn) investment by Chinalco in favour of a tie-up with fellow Anglo-Australian miner BHP Billiton. Rio Tinto is now finalising a deal with BHP to merge⁸ their iron ore operations in Western Australia.

However, Mr Crean did not believe that the two incidents were related

China is Australia's biggest trade partner, worth $53bn in 2008. Of this, $14bn came from iron ore exports, powered by Rio Tinto and BHP Billiton.