San Francisco (AFP) - US prosecutors said Tuesday that a staff member of video game maker Machine Zone has been charged with stealing trade secrets after learning he was to lose his job.

Jing Zeng, 42, could be sentenced to a maximum of ten years in prison and a fine of $250,000 if convicted in the case filed in US federal court in San Francisco.

Zeng downloaded more than 100 files containing proprietary information from a confidential data base at the Northern California company behind "Game of War: Fire Age," US attorney Melinda Haag and San Francisco FBI special agent in charge David Johnson said.

Zeng used a company laptop to download the digital files, transferred them to an external storage drive, then wiped and reformatted the laptop before returning it to Machine Zone, according to a criminal complaint unsealed on Tuesday.

Zeng was arrested as he prepared to board a flight from San Francisco to China on August 20, prosecutors said.

Zeng was released on $100,000 bail and placed on electronic monitoring pending trial.

"Game of War" is a popular massive multi-player online action strategy game for play on computers or mobile devices, and is known for ads starring model and actress Kate Upton.