US former military chief Mike Mullen’s computers have been targeted by foreign hackers and it is being probed by Federal Bureau of Investigation (FBI).

According to officials and others familiar with the probe cited by the Wall Street Journal, the hackers targeted the computers of retired Adm. Mike Mullen, the former chairman of the Joint Chiefs of Staff that were used by him while working on the grounds of the US Naval Academy since his retirement last year.

One official said that evidence gathered by the FBI points to China as the origin of the hacking, and that it appeared the perpetrators were able to access a personal email account of Mullen.

Geng Shuang, the spokesman for the Chinese Embassy in Washington, was quoted by the Wall Street Journal as saying that he was not aware of the investigation into the hacking of Mullen’s computers, and that his government prohibits cyberattacks.

"China is a major victim of hacker attacks. The Chinese government would like to work with other countries, including the US, to explore effective ways to combat cyberattacks," Shuang said.

In October this year, US defence secretary Leon Panetta had warned that the country could face a ‘cyber-Pearl Harbor’ and drafted new rules which would enable military to move quickly to thwart any such attacks.