An US geologist convicted of stealing secret information about the Chinese oil industry has been sentenced to eight years in prison under China's powerful state secrets law.

Jon Huntsman, the US ambassador, attended the hearing yesterday, in which Xue Feng was also fined Rmb200,000 ($29,500, €23,600, ￡19,500). He yesterday called for Mr Xue's release.

The conviction – which came a year after Mr Xue's trial ended – is seen as a reminder of the legal risks that foreign companies in China face and the opaque nature of state secrets legislation. The case against Mr Xue, stemmed from his attempt to buy a database about China's oil industry while working for IHS, the US-based energy consulting company, in 2007, according to a San Francisco-based advocacy group, The Dui Hua Foundation.