Image caption The stolen technology helps block out unwanted frequencies on mobile phones

The US has charged six Chinese nationals over the alleged theft of technology used in mobile phones.

The six, including three university professors, are accused of using the technology to benefit universities and companies controlled by Beijing.

One of the group, Tianjin University professor Hao Zhang, has been arrested but the rest are believed to be in China.

Alleged Chinese economic espionage has long been a concern in Washington.

According to a US Justice Department indictment, the scheme began more than a decade ago.

'Great costs'

Prosecutors say Mr Zhang and another Tianjin University professor, Wei Pang, plotted together to steal FBAR technology from their US employers, which enable mobile phones and other devices to filter unwanted signals.

The pair and others allegedly then set up a company at Tianjin to manufacture FBARs using the stolen technology.

"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 John Carlin, the Assistant Attorney General for National Security.

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

If convicted the six face long jail sentences, but the BBC's Barbara Plett says it is difficult to see how the bulk of the group will be prosecuted.