The US Congress approved a landmark deal ending a three-decade ban on US nuclear trade with India, unleashing billions of dollars of investment and drawing the country closer to the West.

The vote hands a victory to President George W Bush on a top foreign policy priority, and will be welcomed by Indian Prime Minister Manmohan Singh who fought hard for the deal.

Final approval came as the Senate voted 86-13 to ratify the agreement, sending the legislation to Bush to sign into law. The Senate's move came just ahead of an expected trip to India this weekend by US Secretary of State Condoleezza Rice.

Bush said he looked forward to signing the bill.

'This legislation will strengthen our global nuclear non-proliferation efforts, protect the environment, create jobs, and assist India in meeting its growing energy needs in a responsible manner,' Bush said in a statement.

The Bush administration says the pact will secure a strategic partnership with the world's largest democracy, help India meet its rising energy demand and open up a market worth billions.

For India, it will cap a gradual rapprochement with the West since the days of socialist self-reliance, a process that began with economic reforms in the 1990s and has gathered pace with the spread of wealth and Western culture ever since.

But critics say the deal does grave damage to global efforts to contain the spread of nuclear weapons, by letting India import nuclear fuel and technology even though it has tested nuclear weapons and never signed the Non-Proliferation Treaty (NPT).

'The US-Indian Agreement for Nuclear Cooperation is, nonetheless, a non-proliferation disaster,' said Daryl Kimball, head of the Arms Control Association.

'Contrary to the counterfactual claims of proponents and apologists, it does not bring India into the non-proliferation mainstream.'    

The ACA is a non-partisan Washington-based arms control policy organisation.

 India has a yawning energy deficit, and the accord opens up a market worth billions to American companies such as General Electric and Westinghouse Electric, a unit of Japan's Toshiba Corp.

'In terms of India-United States, it will be a boost for business ties. It's not just about nuclear technology but the transfer of high technology to India,' said Mohan Malik, professor at the Asia Pacific Centre for Security Studies in Honolulu.

'It's a good example in terms of the US and India on how big countries can collaborate, increase the pie and increase the field and compete in it,' Chang Young Ho, a nuclear energy expert at Singapore's S Rajaratnam School of International Studies.

Secretary of State Rice spent much of the past month in an all-out effort to persuade Congress to approve the pact, which the Bush administration says will transform the US-India relationship. Bush wanted the deal approved before leaving office in January. Congress is expected to adjourn soon for elections.

The accord enjoys bipartisan support in Congress, where many lawmakers favoured it as a way to create jobs in the US civil nuclear industry while cultivating the small but affluent Indian-American community. - Reuters