Six Chinese nationals, three of them professors, were charged with economic espionage in a US indictment unsealed Tuesday alleging the theft of technology used in mobile phones for Beijing’s benefit.

Six Chinese nationals, three of them professors, were charged with economic espionage in a US indictment unsealed Tuesday alleging the theft of technology used in mobile phones for Beijing's benefit.

According to a 32-count indictment, the six led a long-running effort to obtain US trade secrets for universities and companies controlled by the Chinese government.

Among those charged were Tianjin University professor Hao Zhang, who was arrested upon entry into the United States on Saturday, the US Justice Department said in a statement.

The scheme led to the theft of so-called FBAR technology, which enables mobile phones and other devices to filter radio signals and improve performance, according to the Justice Department.

"As today's case demonstrates, sensitive technology developed by U.S. companies in Silicon Valley and throughout California continues to be vulnerable to coordinated and complex efforts sponsored by foreign governments to steal that technology," said federal prosecutor Melinda Haag.

In a scheme that allegedly dates back to 2006, the six are accused of working to steal trade secrets from California-based Avago Technologies and Massachusetts-based Skyworks Solutions.

A shell company called Novana was created in the Cayman Islands but led by the Chinese academics and Tianjin University, with Chinese government support, to manufacture rival technology products, according to US investigators. The Chinese company was called ROFS Microsystems.

"According to the charges in the indictment, the defendants leveraged their access to and knowledge of sensitive US technologies to illegally obtain and share US trade secrets with (the Chinese government) for economic advantage," said Assistant Attorney General for National Security John Carlin.

"Economic espionage imposes great costs on American businesses, weakens the global marketplace and ultimately harms US interests worldwide."

Zhang, 36, is a former Skyworks employee and a full professor at Tianjin University.

The others charged included Wei Pang, 35, a former Avago employee who is also a full professor at Tianjin University; Jinping Chen, 41, a professor at Tianjin University and a member of the board of ROFS; Huisui Zhang, 34, a Chinese national who studied with Pang and Hao Zhang at the University of Southern California; Chong Zhou, 26, a Tianjin University graduate student; and Zhao Gang, 39, general manager of ROFS Microsystems.

The indictment includes charges of economic espionage, theft of trade secrets and conspiracy.

Pang and Zhang met at USC during their doctoral studies in electrical engineering, where they conducted research on the technology under funding from the US Defense Advanced Research Projects Agency (DARPA).

After earning their doctorates, Pang joined Avago and Zhang took a job at Skyworks.