Chinese authorities are investigating executives from five domestic steelmakers as an inquiry which began with the detention of four Rio Tinto employees for spying broadens, state media reported.
The news came as Australia pressed again for details of the case. Australian national Stern Hu, Rio Tinto's chief iron ore negotiator, and three Chinese employees of the mining firm were detained on 5 July.
The team are representing Rio over annual iron ore price negotiations with the China Iron and Steel Association (CISA), an official body which acts on behalf of steel mills. According to Chinese media, they are accused of bribing steel company employees to obtain confidential information on the Chinese negotiators' position.
The official China Daily newspaper said investigations had now been extended to Chinese steelmakers Baosteel, Anshan, Benxi , Laiwu and Jinan.
A Laiwu official told Reuters that some company officials had been asked by police to assist in investigations, while spokespeople for Shougang – where an executive was detained last week – and Anshan said they had no information. Officials at the other mills could not be immediately reached for comment.
The Chinese government has confirmed that Hu and his co-workers are accused of "stealing state secrets" but has given no details. The state news agency Xinhua said he was also facing charges of obtaining sensitive industrial information through "abnormal means".
Rio Tinto has said it was surprised and concerned over the detention of its employees and had not been told by Chinese authorities of any charges against them.
The detentions came after Rio – acting as lead negotiator on behalf of BHP Billiton and Vale SA as well as itself – failed to reach agreement on annual iron ore contracts with CISA by the 30 June deadline.
Beijing was angered when Rio last month abandoned a $19.5bn (£12bn) deal with a Chinese state-owned company, Chinalco, because of fierce opposition from its shareholders. Some analysts have concluded the detentions are primarily related to the iron ore supply talks.
Nick Day, chief executive of Diligence, the risk consultancy, said that the Chinese authorities in general were under pressure because the global economic downturn had dented demand for the country's exports and increased unemployment which could cause social unrest.
He added that the detentions, coming so soon after the collapse of the Chinalco deal, were unlikely to be a complete coincidence. "It could just be the result of an official from Chinalco seeking some sort of revenge and pointing out who Rio is messing with. The dividing line between the authorities and companies in China is very blurred."
