The US says it expects India to enforce UN sanctions against Iran, but would leave it to New Delhi to decide how to convince Tehran to give up its pursuit of nuclear weapons.
"This is about the danger of a nuclear arms race in the Middle East, which will affect countries outside of the region, including India," State Department spokesman Phillip J Crowley told reporters on Monday.
"So everyone has a responsibility to do what each country can to convince Iran to change its present course," he said. "I'll leave it to India to describe what steps it is going to take."
Asked to comment on Indian Foreign Secretary Nirupama Rao's reported remarks that such "unilateral sanctions" can have "a direct and adverse impact" on India's energy security, Crowley said the US understands that "every country obviously pursues its own self-interest of its citizens".
"By the same token, all countries have international obligations to fully respect and to heed the sanctions that were passed by the Security Council last month."
The US was taking its own steps to fully implement UN sanctions and additional steps within its own laws, he said. "And we would expect all countries to respect and commit themselves to undertake and to enforce the sanctions that have been passed by the UN Security Council."
Crowley also offered no immediate comment "as to whether we have concerns about" the proposed Iran-Pakistan-India gas pipeline.
The US has ongoing concerns about the nature of Iran's nuclear programme, he said noting Russian President Dmitry Medvedev too had voiced a concern that Tehran could reach a "tipping point" in its nuclear drive.
"This is just indicative of the cooperation and shared perspective that the United States and Russia have reached on this issue," Crowley said.
Iran's continued pursuit of sensitive uranium enrichment work was narrowing the "leap from a civilian programme to a military programme," he said.
"We have definite concerns that if this trajectory continues, that Iran will at some point approach that moment-that tipping point, if you will-where it has a de facto military capability," Crowley said.
"We are doing everything in our power to delay and deter that moment from occurring," he said.