Chinese hackers tried to break into computers in the office of India's National Security Adviser and some other government departments last month, National Security Advisor M K Narayanan has told a leading British daily.
"This was not the first instance of an attempt to hack into our computers," The Times quoted him as saying.
Narayanan said his office and other government departments were targeted on December 15, the same date that US companies reported cyber attacks from China.
He said that the attack came in the form of an e-mail with a PDF attachment containing a 'Trojan' virus, which allows a hacker to access a computer remotely and download or delete files. The virus was detected and officials were told not to log on until it was eliminated, he said.
"People seem to be fairly sure it was the Chinese. It is difficult to find the exact source but this is the main suspicion. It seems well founded," he said, adding that India was co-operating with the US and UK to bolster its cyber defences.
China has denied any role in the hacking attacks, which began on December 15 and also targeted US defence contractors and finance and technology companies, including Google.
"Hacking in whatever form is prohibited by law in China," Foreign Ministry spokeswoman Jiang Yu was quoted as saying.
Google had last week threatened to shut down its operations in China after uncovering hacking attempts into e-mail accounts of Chinese human rights activists.
Narayanan said he expected China to be an increasingly high priority for India's security apparatus but that the main threat still came from Pakistan-based militants.
Terror shadow on Games?
Narayanan expressed apprehension that Pakistan-based terrorists may try to disrupt the Commonwealth Games in New Delhi this year to claim that 'India is not a safe place'.
"We believe Pakistan's policy of using terror as a policy weapon remains," he told The Times.
India is particularly anxious to prevent a terrorist attack from disrupting the Commonwealth Games in October, the report said.
"From Pakistan's point of view, it's important to disrupt the Games so you can claim that India is not a safe place," Narayanan said, adding that Pakistan had done nothing to dismantle militant groups since the Mumbai attacks, and criticised Britain, in particular, for accepting its excuse that such groups were beyond its control.
