WASHINGTON, May 1 (Xinhua) -- U.S. Undersecretary of State for Political Affairs Nicholas Burns had two-day talks with Indian Foreign Secretary Shivshankar Menon here over nuclear energy cooperation, the State Department said Tuesday.

    "The U.S. is encouraged by the extensive progress that was made on the issues" by Burns and Menon, State Department spokesman Sean McCormack said in a statement.

    "We look forward to resolving the outstanding issues in the weeks ahead. In that regard, Under Secretary Burns will visit India in the second half of May to reach a final agreement," McCormack said.

    The United States and India reached a historic agreement on civil nuclear cooperation in March 2006, under which India will get access to U.S. civil nuclear technology, and open its nuclear facilities to inspection.

    U.S. President George W. Bush in December 2006 signed into law a bill approved by Congress allowing the deal to go through, a major step towards letting India buy U.S. nuclear reactors and fuel for the first time in 30 years.

    But U.S. Congress attached several conditions to the law which have not gone down well with New Delhi, and the two countries have returned to negotiations.

    Under the bill, the U.S. president would be required to end the export of nuclear materials if India tests another nuclear device. India had nuclear tests in 1998.

    It also does not guarantee uninterrupted fuel supplies for reactors and prevents India from reprocessing spent fuel.

    Indian critics say the agreement will put restrictions on the country's nuclear weapons program.

    The White House hailed the U.S.-India nuclear cooperation agreement as a demonstration of growing importance of India as a partner and ally.