The disclosure came after the US House of Representatives late on Wednesday overwhelmingly agreed the United States should sell nuclear technology to India and rejected a move by critics to delay the vote over concerns New Delhi had not sufficiently helped the United States to contain Iran.

Congressional critics have accused the administration of withholding conclusive word on sanctions against Indian firms until after the vote to avoid endangering its passage.

The United States considers Iran -- patron of the Hezbollah Islamic militant group fighting Israel in Lebanon -- a major international threat, accusing it of building nuclear weapons under cover of an energy programme. Tehran denies the charge.