Cisco Systems is fighting a lawsuit in the United States filed by a human rights group over Internet networking equipment it sold to the Chinese government. The lawsuit asserts that the system, tailored to government demands, allowed the authorities to track down and torture members of the religious group Falun Gong.

Bain defended its purchase of Uniview, stressing that the Chinese company’s products were advertised as instruments for crime control, not political repression. “China’s increasingly urban population will face growing needs around personal safety and property protection,” the company said in a statement. “Video surveillance is part of the solution to that, as it is anywhere in the world.” The company also said that only one-third of Uniview’s sales were to public security bureaus.

William A. Reinsch, president of the National Foreign Trade Council in Washington, said it was up to the American government, not individual companies, to set the guidelines for such business ventures. “A lot of the stuff we’re talking about is truly dual use,” said Mr. Reinsch, a former Commerce Department official in the Clinton administration. “You can sell it to a local police force that will use it to track down speeders, but you can also sell it to a ministry of state security that will use it to monitor dissidents.”

But Adam Segal, a senior fellow at the Council on Foreign Relations and an expert on the intersection of technology and domestic security in China, said American companies could not shirk responsibility for the way their technology is used, especially in the wake of recent controversies over the sales of Western Internet filtering systems to autocratic rulers in the Arab world. “Technology companies have to begin to think about the ethics and political implications of selling these technologies,” he said.

Uniview is proud of its close association with China’s security establishment and boasts about the scores of surveillance systems it has created for local security agencies in the six years since the Safe Cities program was started.