The efforts of the Bush administration to get Congress pass legislation that will allow the United States to sell nuclear technology to India and accept it as a full-time partner in the international nuclear community appear to have received a setback, following a meeting of Nuclear Suppliers Group nations.

According to a Financial Times report Monday, the diplomats and analysts briefed on the outcome of last week's discussions of the 45-nation NSG in Vienna said concerns raised by a number of countries, including China, would complicate the Bush administration's parallel initiative to have Congress pass legislation.

• Indo-US nuke tango

The NSG was established as a result of India's first nuclear test in 1974. The NSG and its guidelines governing the supply of sensitive nuclear materials have been a major impediment to the development of India's civilian nuclear programme.

Under a bilateral agreement reached earlier in March by the Prime Minister Manmohan Singh [Images] and US President George W Bush [Images] in New Delhi, India will receive support for its civilian reactors in exchange for placing eight more facilities under international safeguards and separating its civil and military nuclear facilities.

• Bush in India

Besides the US, several major nuclear powers, including the UK, France [Images] and Russia [Images], argue that the proposed deal, making an exception for India -- which has not signed the nuclear non-proliferation treaty -- would strengthen global efforts to prevent the spread of nuclear weapons.

However, some other nations express concern that it sets a precedent that will lead to a further unravelling of the treaty, which has already been tested by North Korea's withdrawal from the NPT in 2003, the impasse over Iran's nuclear development, and covert sales by Pakistani nuclear scientists.

The US had hoped that a plenary meeting of the NSG to be held in Rio de Janeiro in late May would admit India into the nuclear club following approval on the domestic side by Congress.

But that timetable of NSG looks unlikely to be met, diplomats say, although they do not see the entire deal being derailed.

One spoke of the "realpolitik factor" and how the growing strategic relationship between India and the US could not be overlooked.

According to US Assistant Secretary of State Richard Boucher, many questions were raised during the Vienna preparatory talks. He however, gave no details but said he did not know when the final agreement would be reached.