A U.S. company will seek legal action against Lenovo, Acer, and Sony next week over their shipment in China of controversial software that the company says stole its programming code.Solid Oak Software may also take action against other PC makers that have started shipping the software, a company spokeswoman said in an e-mail late Thursday. She declined to give details of the action, but the company previously said it might seek a U.S. court injunction to stop PC vendors from shipping the program.

The software, an Internet filtering tool that blocks pornographic and political content, copied files from Solid Oak's own Internet content control product, according to the company.

In recent weeks China ordered domestic and foreign PC makers to bundle the software, called Green Dam Youth Escort, with all computers sold in the country. It postponed the requirement just hours before the original deadline this week, but said it did so only because PC makers needed more time to ship the program.

Lenovo, Acer and Sony have all started shipping the program despite the postponement. Lenovo is providing Green Dam pre-installed or on an enclosed disc for most of its computers that support the program, a spokeswoman said.

Sony is including a setup file for Green Dam on its machines that users can choose to activate or remove, a company spokeswoman said. An Acer representative confirmed the company is also including the program with new machines.

Acer and Lenovo were the world's third- and fourth-largest PC vendors in the final quarter last year, according to IDC.

All three companies declined to comment on Solid Oak's plans for legal action.

China says it mandated Green Dam to protect children from "harmful" information online. But critics and foreign industry groups have voiced concerns about the program ranging from free speech and user privacy to security and system stability. Users, however, can choose to remove the program.

Whether China will set a new deadline for PC makers to offer the software remains unclear.