Beijinghas expressed deep concern about the latest economic espionage allegations targeting Chinese nationals in the United States, a case that observers say highlights growing economic friction between the two countries.

China is seeking further details and will work to safeguard the rights and interests of its nationals, Foreign Ministry spokesman Hong Lei said on Wednesday.

Hong's remarks followed the announcement that the US has charged six Chinese nationals with stealing mobile phone technology from two US chipmakers where some of them worked. A 32-count criminal indictment says the six were acting on behalf of universities and companies controlled by the Chinese government.

One of the suspects, Zhang Hao, 36, was visiting the US for a conference when he was arrested on Saturday in Los Angeles after arriving on a flight from China, the US Justice Department said on Tuesday. The other five are believed to be in China.

US prosecutors say Zhang, a former employee of Massachusetts-based Skyworks Solutions and now a TianjinUniversity professor, and the others established a company, ROFS Microsystems, in Tianjin with secrets stolen from Skyworks and another US firm, Avago Technologies.

Two other suspects, Pang Wei and Chen Jingpin, deny stealing technology, according to the indictment.

Pang, 35, is a former employee of California-based Avago and a professor at Tianjin University.

A publicity department official at the university, surnamed Song, said further details are being sought and a public response will be issued.

This is the 11th case of alleged economic espionage brought in the US under a 1996 law, and the six suspects could face lengthy prison sentences if convicted.

Teng Jianqun, an expert on US studies at the China Institute of International Studies, said the US is overly suspicious about the protection of intellectual property rights.

Li Haidong, a professor of US studies at China Foreign Affairs University, said the two countries have seen growing friction in the economic sector, but these problems, along with others, have to be properly addressed to avoid disrupting the development of high-level ties.

Last year, the US indicted five Chinese military officers for allegedly hacking information from US nuclear, metal and solar companies. The Defense Ministry in Beijing issued a denial and summoned the US military attache.

Li Xiang in Tianjin contributed to this story.