President George W. Bush on Monday (December 18) signed into law a nuclear deal with India in a major step toward allowing New Delhi to buy U.S. reactors and fuel for the first time in 30 years. "The relationship between the United States and India has never been more vital and this bill will help us meet the energy and security challenges of the 21st century," Bush said at the bill-signing ceremony. The White House had pushed for the legislation, which was overwhelmingly approved by Congress this month, in a bid to expand ties with the world's largest democracy and increase trade for U.S. companies. Critics say the deal undermines efforts to prevent the spread of nuclear weapons. "The United States and India are natural partners, the rivalries that once kept our nations apart are no more," Bush said, citing similarities within the two democracies. "India is an important ally in the war against extremists and radicals," Bush said. But Indian Prime Minister Manmohan Singh said that tough negotiations with the United States still lie ahead over the deal, promising the country's sovereignty would not be compromised. Singh said India would not be bound by "extraneous" conditions attached to the deal when it was passed by the U.S. Congress this month, rejecting efforts to constrain New Delhi's policy towards Iran or its own nuclear weapons programme. Congress attached several conditions to the law, which have not gone down well with Singh's communist allies and with the main Hindu-nationalist opposition. Under the bill, the U.S. president would be required to end the export of nuclear materials if India tests another nuclear device as it did in 1998. The deal reverses decades of U.S. policy that, until July 2005, opposed nuclear cooperation with India because it developed nuclear weapons in contravention of international standards and never signed the Non-Proliferation Treaty. But it still needs the approval of the 45-nation Nuclear Suppliers Group, the International Atomic Energy Agency and again by the U.S. Congress before nuclear transfers can actually take place. Singh said the law reflected India's arrival on the world stage "as a power to be reckoned with". Under the deal, India has agreed to allow international inspections at 14 civilian nuclear plants while eight military facilities would still be off-limits. However, Prime Minster Singh said the government would not allow indigenous research and development to be stopped. "In going forward with this programme of civilian nuclear co-operation, we will do nothing which will hurt the ability of our department of atomic energy to pursue research and development, to pursue development of fast breeder reactors and to pursue the complete three cycle programme from Uranium to Plutonium to Thorium and can assure the House that I stand by that commitment," he said. According to Congress' stipulations, the U.S. president is also required to report to Congress annually on whether India was cooperating with international efforts to restrain Iran's nuclear programme. But Singh said that it was the India government's duty to safeguard the country's autonomy. "I repeat, no legislation of a foreign country can take away from us our sovereign right to conduct foreign relations, be it with Iran, or with other countries, solely in accordance with our national interests," he said. Critics say the bill also fails to guarantee uninterrupted fuel supplies for civilian reactors and prevents India from reprocessing spent fuel. The deal has also attracted criticism in the United States for undermining efforts to curb the spread of nuclear weapons. Experts say India has already produced about 50 nuclear weapons and plans to reach up to 400 in a decade. Many fear selling India fuel for civilian energy use will free up New Delhi's indigenous uranium stocks for weapons.