Manmohan Singh's assets are hack-free

The Guardian newspaper reported Friday that US spies eavesdropped on the phone conversations of 35 world leaders after White House, Pentagon and State Department officials gave them the numbers.

The new revelations, based on a classified document provided by intelligence leaker Edward Snowden, come amid fury from German Chancellor Angela Merkel, whose communications were allegedly targeted.

Asked if Prime Minister Manmohan Singh was concerned, his spokesman replied: "The prime minister doesn't use a mobile phone and he doesn't have an email account."

"His office uses email, but he has no personal email... We have no information and no cause for concern," he added.

India has witnessed a mobile telecom boom in the past decade with the latest figures from the national telecom regulator showing 876 million phone connections in the country of 1.2 billion people.

But the industry is also at the heart of one of the worst graft scandals afflicting Singh's embattled administration with ex-telecom minister A. Raja on trial over allegedly corrupt allocation of phone licences in 2008.

India initially played down the impact of spying by the US National Security Agency, saying that information gleaned from its activities had helped prevent terror attacks and loss of life. But following allegations that computers and phones in the Indian embassy and its UN mission in New York had been compromised, it took a slightly tougher line, saying it would seek answers from Washington.

Soft-spoken Singh, promoted to the top job owing to his reputation as 'Mr Clean' and a successful stint as a reformist finance minister in the 1990s, has seen his popularity plunge in recent years.

Instead of the wise and respected economist capable of steering India through momentous change, he is now routinely portrayed in the local media as the out-of-touch and weak head of a graft-ridden government.

On Thursday, while returning from a trip to Russia and China, he told journalists that he would be happy to be questioned by police over an alleged coal scam amid growing speculation he will be called to give evidence. He also defended his legacy.

"I am doing my duty. I will continue to do my duty. What impact my 10 years of prime ministership will have is something which is for historians to judge," he added.