The Indo-US nuclear deal, which enjoys the broad support of the US Congress, is expected to be passed this summer, a US official has said.

Revealing this at a roundtable meeting with the visiting Indian parliamentary delegation, Richard Haas, president of the Council on Foreign Relations, however, cautioned: "In the long run, India's approach to the Iran (nuclear) issue could cause problems between the two nations."

Haas said he was optimistic that a significant majority in both Houses will vote for the deal.

• Also see: The Indo-US nuclear tango

"The nuclear deal will be passed soon and it will pave the way for a foundation of stronger Indo-US relationship, which will be a turning point and a challenging few years for the two countries," Haas, who has also served as the director of the Policy Planning for the State Department, said.

The approval would come on the basis of strategic long-term relation with India, he said. However, Haas said India's approach to the Iran issue could cause a "problem" between the two countries in the long run.

"India's reason to take a different approach due to demographic relationship with Iran, oil and also because of its large Shia population is definitely understandable," he said.

• Also See: The Iran Vote and After

To this, BJP's Manvinder Singh retorted, saying, "It is an insult to India's Muslim if the ties between Iran and India are reduced to sectarian issues, as their relation goes back when both existed as civilization states.

"And, the contemporary contribution of Iran and India cannot be negated... When the world was playing ball with the Taliban [Images] regime, it was India and Iran, who kept the Northern Alliance (of Afghanistan) alive," Singh said.

In addition to the discussion on the nuclear deal during the meeting, the two sides also discussed the basic infrastructure in areas like railways, roads, airports and the bottlenecks that US investors face most of the time. The Indian delegates assured them of better services.

Earlier, at a luncheon meeting, the delegates invited US-based Indian companies and investors to invest in India as it is the best time to do so.

Each MP apprised those present about the changing economic scenario.

"The ultimate agenda should be to see India attain a position of prominence throughout the world," Congress MP Sachin Pilot said, urging business investors to push the agenda and issues in favour of Indian people rather than the governments, which come and go.

The visiting Indian delegation comprising MPs from Congress, BJP, Shiv Sena, Samajwadi Party and BJD will also meet US Secretary of State Condoleezza Rice [Images].

The delegates are hopeful of getting a positive response and assurance from Rice over the nuclear deal, which they consider is very symbolic and can flourish Indo-US ties further if passed sooner.