India's Prime Minister Atal Bihari Vajpayee said that the United States offered to supply his country with nuclear bombs in an attempt to dissuade it from launching nuclear tests in 1998.
Strobe Talbott, who was the US State Department's No 2 official at that time, said there was no basis for Vajpayee's statement.
Vajpayee told an election rally in Bhubaneshwar, the capital of eastern Orissa state, that he rejected Washington's offer because India needed to demonstrate it was capable of building its own nuclear weapons.
"When I told them (Americans) you also have made that bomb, they replied when required you can take that from us. I told them frankly this bomb needs to be made and not borrowed," Vajpayee said.
He said the offer came as the United States encouraged India not to go ahead with nuclear tests in 1998.
"But we went ahead with the tests," Vajpayee said.
Both India and its rival Pakistan have an undeclared number of nuclear weapons.
Talbott said the credibility of Vajpayee's comment is "zero, less than zero." India's nuclear test caught the Clinton administration completely by surprise, he said.
"How were we supposed to make this offer if we didn't know they were going to do it?" he asked.
Talbott added that the administration first learned of India's action from news reports.
Talbott travelled to the region later in May 1998 to urge India and Pakistan to exercise restraint in light of the new situation.
The prime minister reiterated the government's position that India would never be the first to launch a nuclear attack but, "we will not hesitate to use it if somebody used the bomb against us."
Vajpayee made the comments during a rally for India's parliamentary elections, which will be held in four phases between April 20 and May 10.