Vienna: Nuclear supplier states on Saturday approved a US proposal to drop a ban on trade with India, diplomats said.

The decision from the 45 nations advances a US-Indian nuclear energy deal.

It also follows a tense debate over conditions for the move demanded by Nuclear Suppliers Group members to minimise any damage to the Non-Proliferation Treaty.

India has tested atomic weapons but has refused to sign international nonproliferation treaties.

One hurdle, however, remained before the US-India deal could take force: Ratification by the US Congress.

It must act before adjourning in late September for elections or the deal could be left to an uncertain fate under a new US administration.