India has been seeking entry into the 48-member elite nuclear club, which controls nuclear trade, but China has repeatedly stonewalled its bid.
Juster acknowledged that the US and India faced challenging and complicated issues related to the transfer of sensitive US technology with both military and conventional applications.
"India sought increased access to this technology, while the US wanted to ensure that any transfers would be used solely by the designated recipients for the agreed-upon purposes.
"This required a sophisticated system of export controls, which India, candidly, did not have at the time," Juster said in his first policy speech since taking over as the US ambassador to India.
The initial interactions on the subject were "quite formal and somewhat strained due to the wide gulf" in the positions of the two nations, Juster acknowledged.
He said the US had moved from a restrictive policy on the export of dual-use items to India to a much more "liberal one".
"Look how far we have come," he said, citing India's membership in two of the four multilateral export control regimes -- the Wassenaar Arrangement on dual-use items, and the Missile Technology Control Regime.
"We also expect India to join the Australia Group on chemical and biological weapons in the very near future. And, we are working closely with India and our international partners to secure India's membership in the Nuclear Suppliers Group," he said.
India entered the MTCR and the Wassenaar Agreement in 2016 and 2017 respectively.
Juster said the environment and energy were a pillar ripe for enhanced strategic cooperation.
The US-India Strategic Energy Partnership will convene early this year at the ministerial level, he added.
"The US is uniquely positioned to offer India a comprehensive energy partnership. This includes all forms of energy -- coal, crude oil, natural gas, nuclear power and technology related to clean fossil fuel, smart grids, energy storage and renewable resources," he said.
US nuclear gaint Westinghouse Co is also building six nuclear power reactors in Andhra Pradesh.
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