Four employees of Australian miner Rio Tinto have been arrested in China on charges of stealing state secrets, the official Xinhua news agency said on Thursday, citing Shanghai state security authorities.

The suspects included Stern Hu, an Australian national and general manager of the company's Shanghai office, who was also in charge of Rio Tinto's iron ore business in China, Xinhua quoted the Shanghai municipal state security agency as saying.

The case was being investigated according to law, Xinhua said. It gave no further details.

Rio Tinto declined to make any immediate comment on the arrests.

(Reporting by Tom Miles and Benjamin Kang Lim; Editing by David Fox)