The draft accord allowing the United States to provide atomic technology and fuel to India will still require a final nod by the leaders of the two countries, the officials said.

"The agreement has been finalized but it awaits review by both governments," Rahul Chhabra, the spokesman for the Indian embassy, told AFP at the end of four days of talks late Friday.

The talks were led by US Under Secretary of State Nicholas Burns and Indian Foreign Secretary Shivshankar Menon.

"The discussions were constructive and positive, and both Under Secretary Burns and Foreign Secretary Menon are pleased with the substantial progress made on the outstanding issues in the 123 agreement," a joint statement said.

"We will now refer the issue to our governments for final review," the statement.

The implementation agreement, or "123 agreement," is intended to capture all operational aspects of the nuclear deal, which was agreed upon by US President George W. Bush and Indian Prime Minister Manmohan Singh two years ago to highlight strategic ties between the world's two biggest democracies.

After government approval, the pact will have to be cleared by theDemocratic-controlled US Congress, where lawmakers have vowed tight scrutiny.

The US Congress already approved the nuclear deal in principle last year and a bill to that effect was signed into law by Bush.

But the law requires a comprehensive implementation agreement that has to be approved again by the Democratic-controlled Congress.

India also needs to sign an additional protocol with the International Atomic Energy Agency and get the approval of the 45-nation Nuclear Suppliers Group.

The deal would reverse three decades of US sanctions imposed over nuclear tests carried out by India, which is not a member of the Nuclear Non-Proliferation Treaty.

The United States and India "look forward to the completion of these remaining steps and to the conclusion of this historic initiative," said the joint statement.

The deal could open up a whopping 100 billion dollars in opportunities for American businesses, according to the US Chamber of Commerce.

The talks in Washington were supposed to end Wednesday but extended by two days after the two sides broke the "logjam" that had blocked an accord for the last two years, officials had said, without elaborating.

The extended talk showed "there really is goodwill on the part of both sides to resolve outstanding differences and finish this key piece of the US-India civilian nuclear arrangement," said Tom Casey, a State Department spokesman.

He rejected any notion that the talks were troubled, amid some reports that Washington and New Delhi were desperately trying to salvage the deal.

"I certainly would take issue with the notion that these talks are somehow in trouble or that we don't ultimately feel confident that we will be able to reach an agreement," Casey said.

For the nuclear deal to be implemented, India should separate nuclear facilities for civilian and military use and set up a regime of international inspections to allay concerns that material and technology received are not diverted to boost its nuclear weapons arsenal.

Despite several rounds of talks, India has stood fast against accepting any curbs on its reprocessing of spent nuclear fuel.

India also wants assurances that Washington will continue to supply fuel for its atomic plants in the event New Delhi conducts further nuclear weapons tests.

Under US law, if India conducts another nuclear test, the US president "must terminate all export and reexport of US-origin nuclear materials, nuclear equipment, and sensitive nuclear technology to India."

Indian officials have reportedly proposed to set up a special unit to reprocess spent atomic fuel at home under international safeguards in a bid to break the impasse.