WASHINGTON, Oct 9: India. China and Russia may have obtained nuclear secrets from US through the visitors' exchange programmes, a house sub-committee on the Department of Energy was told, reports PTI.

When the nuclear detonation occurred in India, it is our understanding that the Department of Energy did not know if there were any visitors within the laboratories from India at that time. Keith Fultz, assistant comptroller general for the general accounting office, the investigation arm of US Congress, told the sub-committee.

He was referring to the visitors exchange programme, under which Indian. Chinese and Russian scientists visit US nuclear laboratories on reciprocal basis but did not explain what difference it would have made.