A senior US lawmaker has warned India that its alleged training of Iranian troops could undermine Congressional support for the landmark Indo-US civilian nuclear deal.

Tom Lantos, the ranking Democrat on the powerful House International Relations Committee expressed the view when Foreign Secretary Shyam Saran called on him Thursday, apparently referring to reports in Washington that Iranian ships completed a training programm in Kochi where two of Tehran's warships were said to have been anchored.

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However, India denied imparting training to Iranian soldiers, saying it was just a normal diplomatic call on Kochi port by two Iranian navy ships.

"The so-called training visit was just a normal diplomatic call on Kochi port by two Iranian ships, which were undergoing training in the Arabian Sea. Those ships did not receive formal training in India," an Indian diplomat said.

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During the course of the "very friendly" meeting between Lantos and Saran, the California Democrat said he is was in general "supportive of India and the closer relations between India and the United States and that is why he welcomes the proposed nuclear deal".

"However, he cautioned there can be misunderstandings and conflicts which can undermine support for the deal within Congress", the Congressman's spokeswoman Lynne Weil told PTI adding, Lantos in particular talked of two issues.

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"He mentioned that India's wavering commitment to refer Iran to the United Nations Security Council was a cause for tremendous consternation in Congress, including for Lantos, and of course that has been resolved," she said.

The spokeswoman said, "More recently, concerns have been raised about Iranian troops possibly having received training support from India -- again, I stress possibly having received training support from India.

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"And Lantos mentioned (to Saran) that the concern about possible troop training for Iranian troops could also undermine Congressional support for the nuclear deal," she said.

"At a time when gestures from allies are significant -- not just symbolically but substantively meaningful gestures -- he (Lantos) urges the Indian government to find gestures that will underscore the depth and breadth of India's friendship with the US; and to be conscious of those situations where the possible training of Iranian troops could be a residual effect on how members of Congress and the US public view those relations," Weil said.

There have been members of Congress, including Lantos, who have been sharply critical of New Delhi's relationship with Tehran even while taking note of recent Indian stance in Vienna on Iran's nuclear issue. The fact that India came around and supported the United States twice has made a difference in the perception of law makers including Lantos.