Nuclear supplier nations began a two-day meeting in Vienna on Thursday to try and hammer out consensus on lifting a 34-year-old embargo on nuclear trade with India.
After the US failed to drum up sufficient support for its proposal to start civil nuclear cooperation with India at a meeting last month, the Nuclear Suppliers Group (NSG), which controls the export and sale of nuclear technology worldwide, convened again in Vienna to try and smooth out their differences.
Diplomats who attended the last set of discussions had said that the US-India deal ran into stiff resistance among member states, with some setting conditions for giving approval.
The United States wants a special waiver of NSG rules for India, which refuses to sign the Nuclear Non-Proliferation Treaty (NPT), allowing Washington and New Delhi to cooperate in the civilian nuclear field.
But a number of countries have openly expressed reservations about the 2005 agreement between the United States and India.
Heading the US delegation this time round is US Undersecretary of State for Political Affairs, William Burns.
The fact that the United States is sending its third-ranking official in the State Department to the meeting indicates the urgency which Washington attaches to a deal.
Under NSG rules, all nuclear trade with India is banned because it refuses to sign the NPT, developed atomic bombs in secret and conducted its first nuclear test in 1974.
The United States argues that the new deal will bring India into the NPT fold after 34 years of isolation and help combat global warming by allowing the world's largest democracy to develop low-polluting nuclear energy.
Critics argue that the deal undermines international non-proliferation efforts by providing US nuclear technology to a non-NPT state.
They accuse the nuclear states supporting the deal of ignoring the proliferation dangers in pursuit of commercial and political gains.
The deal must clear three major hurdles before it can come into effect.
The first came at the beginning of August when the International Atomic Energy Agency approved an India-specific safeguards agreement.
The NSG represents the next obstacle before the deal must finally be approved by the US Congress. Unanimous approval is required from the group.
Diplomats said that a number of countries have tabled conditions before the nuclear suppliers would give the green light.