China's new premier Li Keqiang on Sunday rejected US accusations of hacking, saying that Beijing did not support cyber spying after President Barack Obama stepped up rhetoric on the issue.
"China itself is a major victim of cyber attacks," Li told a news conference after China's parliament meeting. "China doesn't support cyber attacks. Indeed we oppose such activities.
"I think we should not make groundless accusations against each other and spend more time doing practical work that will contribute to cyber security," he said.
Last month, a report from US security firm Mandiant said a unit of China's People's Liberation Army had stolen hundreds of terabytes of data from at least 141 organisations, mostly based in the United States.
The document provided the most detailed public account so far linking cyber attacks to China and provoked vehement denials from China.
Obama weighed in on the issue last week, saying that cyber threats affecting US firms and infrastructure were increasing, and some were "state sponsored".
"We've made it very clear to China and some other state actors that, you know, we expect them to follow international norms and abide by international rules," he said in an interview with ABC News.
Li said that the China-US relationship, between the "biggest developing country and the biggest developed country", was vital and they should work to ensure their mutual interests outweighed their differences.
"Conflicts between big powers are not inevitable," he said, adding that visiting Washington officials had "told me candidly in our talks that they came for the US interests. I told them I work for Chinese interests."