The report by the Congressional Research Service raised the issue of whether India had adequate teeth to implement export control regulations in efforts to prevent Iran from acquiring nuclear weapons.

In 2004, the United States imposed sanctions on two Indian scientists for nuclear related transfers to Iran, which is facing sanctions for refusing to comply with UN demands it freeze its uranium enrichment work.

The Congressional report by Sharon Squassoni, a national defence specialist, noted that President George W. Bush's administration had not formally responded to claims that India had a "flawed" nonproliferation record in the nuclear area.

It also cited allegations that New Delhi had a "poorly implemented" national export control system and an "illicit" procurement system for its own nuclear weapons programme, as well as a procurement system that "may unwittingly transfer sensitive information" about uranium enrichment.

"India's nonproliferation record continues to be scrutinized, as India continues to take steps to strengthen its own export controls," the report said ahead of an expected Senate vote this week on the US-India civilian nuclear deal clinched by Bush and Indian Prime Minister Manmohan Singh in March.