SHANGHAI – Court hearings in Shanghai for the Rio Tinto employees who pleaded guilty to taking bribes will today shift to charges of stealing commercial secrets, an Australian diplomat said.

The four, including an Australian executive, Stern Hu, who was handling Rio Tinto’s iron ore business in China at the time of his arrest last year, admitted bribery charges Monday, their lawyers said.

Rio Tinto is one of China’s top providers of iron ore and a key industry negotiator in commodity price talks with the government.

The admissions of bribe taking are a blow for Rio Tinto at a time when it is striving to restore good relations with China. The four also face charges of stealing commercial secrets, and final verdicts in the trial could take weeks.

“Only in the last year have we come upon some difficulties, which we are working hard to resolve,” Rio Tinto’s chief executive, Tom Albanese, told a conference in Beijing on Monday.

Hu made no comment Tuesday in court, Tom Connor, the Australian consul-general in Shanghai, told reporters.

Connor said both sides presented their arguments and rebuttals before the session ended before noon.

The Australian diplomats were not returning for the court’s afternoon session today because hearings into charges Hu and the others stole commercial secrets were closed to them – a decision the Australian side has protested.

Lawyers said Monday that Hu and the three Chinese nationals – Liu Caikui, Ge Minqiang and Wang Yong – acknowledged taking bribes but disputed the amounts they are alleged to have accepted.

According to Connor, Hu was accused of taking 1 million yuan ($146,000) and $790,000. He did not provide further details.

The maximum penalty for commercial espionage is seven years in prison. The maximum penalty for taking large bribes is five years.