Chinese hackers are believed to have attempted to penetrate India’s most sensitive government office in the latest sign of rising tensions between the two rival Asian powers.M. K. Narayanan, India’s National Security Adviser, said his office and other government departments were targeted on December 15, the same date that US companies reported cyber attacks from China. “This was not the first instance of an attempt to hack into our computers,” Mr Narayanan told British newspaper in a rare interview. 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 America and Britain 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,” said Jiang Yu, a Foreign Ministry spokeswoman.