US and India to sign nuclear deal
President Bush signed the accord into law earlier this week
The United States and India are due to sign a civilian nuclear co-operation accord to end 34 years of US sanctions.
US Secretary of State Condoleezza Rice and Indian foreign minister Pranab Mukherjee will sign the deal in Washington after years of negotiations.
India will gain access to US civilian nuclear technology and fuel in return for inspections of its civilian, but not military, nuclear facilities.
India says the accord is vital to meet its rising energy needs.
Critics say it creates a dangerous precedent.
They say it effectively allows India to expand its nuclear power industry without requiring it to sign the Non-Proliferation Treaty (NPT) as other nations must.
The US restricted nuclear co-operation with India after it tested a nuclear weapon in 1974.
US President George W Bush signed the accord into law earlier this week, after it had finally been approved by the US Congress.
The deal was first agreed three years ago and is regarded as a key foreign policy priority for both the Indian and US governments.
Indian Prime Minister Manmohan Singh has said the deal will help India to liberate itself from "the constraints of technology denial of 34 years".
Although India has said it retains the right to conduct nuclear tests, the US has said the deal would be cancelled in such an eventuality.
The Nuclear Suppliers Group (NSG) recently lifted a ban that had denied India access to the international nuclear market.
India and France have also signed a major co-operation pact which paves the way for the sale of French nuclear reactors to Delhi.
France is the world's second largest producer of nuclear energy after the United States.
Russia has also been lobbying the Indian government hard on behalf of its firms.