India's foreign secretary said ties between India and the United States could take a beating if Congress fails to approve a landmark agreement on civilian nuclear technology cooperation.

The official said that while he's confident that the U.S. will eventually exempt India from American laws that restrict nuclear technology, the impact of a failure would be negative.

Under the deal, considered a major U.S. policy shift, the U.S. would ship nuclear technology and fuel to India. In return, India would allow international inspections and safeguards at 14 nuclear reactors it has designated as civilian. India's eight military facilities would not be open to inspections.

India has not signed the nuclear nonproliferation treaty , raising concerns among U.S. lawmakers that the deal could undermine efforts to stop the spread of nuclear weapons.