The two allegedly stole microchip designs with possible military uses

US citizen Lee Lan and Chinese national Ge Yuefei are accused of stealing computer chip designs from their employer Netlogics Microsystems.

The two are alleged to have formed a company to develop chips based on the stolen designs.

They then contacted the Chinese army to sell the chips, prosecutors said.

'Economic espionage'

Their indictment also alleges they stole documents from Taiwan Semiconductor Manufacturing Corporation, which has an office in California's Silicon Valley.

The two companies design and make microchips and processors for use in networking equipment with possible military uses.

Mr Lee and Mr Ge have each been charged with two counts of economic espionage, two counts of theft of trade secrets and one count of conspiracy.

They face up to 15 years in prison if convicted.

"The vigorous enforcement of intellectual property statutes increases the economic vitality of this region, and adds to the security of our nation as a whole," said US attorney Scott Schools.

Only three other people in the US have been convicted of economic espionage - stealing trade secrets to benefit a foreign government.

All three cases were related to computer parts or software in Silicon Valley outside San Francisco.