China accused Washington of breaking into computers at Northwestern Polytechnical University, which US officials say conducts military research. Both governments complained about worrying online spying against one another.

The National Computer Virus Emergency Response Center reported computer break-ins at Northwestern Polytechnical University in June. It was stated that the centre, in collaboration with a commercial security provider, Qihoo 360 Technology Co., identified the attacks back to the National Security Agency, but was not specified how.

China accuses the US of spying on universities, energy companies, and internet service providers, among other targets. Washington accuses Beijing of stealing commercial secrets and has charged Chinese military officers with crimes.