The US National Security Agency targeted the Indian embassy in Washington and the Indian UN office in New York with sophisticated surveillance equipment that might have resulted in hard disks being copied, a report said Wednesday.

The Hindu, which has been collaborating with the Guardian newspaper reporter Glenn Greenwald, said the Indian offices were on a top-secret list of countries chosen for intensive spying.

The NSA "selected India's UN office and the embassy as (a) 'location target' for infiltrating their computers and telephones with hi-tech bugs," the paper said, citing a secret internal document from the spy agency.

It said India's missions were marked for various snooping techniques including one codenamed "Lifesaver," which "facilitates imaging of the hard drive of computers."

The revelations about US spying activities, leaked through documents obtained by former NSA contractor Edward Snowden, have already strained relations between US President Barack Obama and his foreign allies, notably Brazilian President Dilma Rousseff.

The Hindu's report gives more detail on previous revelations published in the Guardian by Greenwald in July that 38 embassies and diplomatic missions were targeted by the NSA, including India's.

New Delhi has previously defended widespread snooping on Internet users and phone calls by US intelligence agencies.