Washington - US President George W Bush assured Indian Prime Minister Manmohan Singh that his administration was working to get prompt congressional approval on a deal that would allow the United States to share civilian nuclear technology to India.

"It's taken a lot of work on both our parts, a lot of courage on your part," Bush said. "And so we're working hard to get it passed as quickly as possible."

Singh arrived in Washington for the White House meeting on Thursday after attending the UN General Assembly in New York, and just as Congress has taken up the historic agreement that has been at the forefront of Bush's foreign policy agenda as be prepares to leave office in January.

The deal, which would allow US firms to sell nuclear material and technology to India, is seen as the cornerstone of stronger diplomatic and economic ties between the two countries.

"I sincerely hope that this agreement ... will be approved in a manner which will be satisfactory from the point of view of both our countries," Singh said.

The Senate Foreign Relations Committee on Tuesday overwhelmingly approved the deal, which still must go to the full chamber. The House of Representatives was expected to take up the measure on Friday.

With the congressional session nearing an end in the coming days, Bush urged lawmakers to quickly debate and approve the nuclear agreement first signed by the two leaders in 2006. Since then, the two countries have been in complicated negotiations to implement the agreement, pending congressional approval.

Legislative aides said they expect Congress to pass the agreement, but some lawmakers have expressed reservations about the deal because India is not a member of the nuclear Non-Proliferation Treaty.

The White House has warned that failing to approve the deal will leave US companies out of India's lucrative energy sector, as France and Russia have moved to complete similar arrangements with New Delhi.

The deal had been hung up earlier this year in Singh's governing coalition. Smaller parties argued that the agreement compromised India's sovereignty because of US demands for the opening to international inspections of India's civilian nuclear reactors - but not military facilities.

That opposition softened in July after Singh prevailed in a parliamentary vote of confidence.

Earlier this month, an organization of 45 countries known as the Nuclear Suppliers Group granted a US-backed waiver for India to purchase nuclear material on the international market. The waiver was required under rules banning sales to non-NPT members.

The United States had refused to cooperate with India's nuclear energy programme since the country first detonated an atomic bomb in 1974.

"For 34 years, India has suffered from a nuclear apartheid. We have not been able to trade in nuclear materials, nuclear reactors, nuclear raw materials," Singh said.

"When this restrictive regime ends, I think a great deal of credit will go to President Bush."