The Obama administration is accusing China's military of carrying out computer-based attacks against the United States.
The accusations were made in the Pentagon's annual report to Congress.
The report says China is using its cyber capabilities to collect intelligence against U.S. diplomatic, economic and defense programs.
It warned that the computer skills needed for this kind of espionage is similar to the kind needed to conduct cyber-warfare.
But Senior Col. Wang Xinjun, a People's Liberation Army researcher, called the accusations "irresponsible and harmful to the mutual trust between the sides."
"The Chinese government and armed forces have never sanctioned hacking activities," China's official Xinhua News Agency quoted Wang.
This is the first time the U.S. has directly accused the Chinese government and its military of using cyber weapons to steal U.S. government strategy.