A landmark agreement on civilian nuclear cooperation between India and the United States faced a new obstacle in the U.S. Senate Friday but saw progress in the House of Representatives.

The agreement looked stalled in the Senate after at least one lawmaker anonymously blocked a bill to approve the deal from reaching a vote, according to congressional aides, who spoke on condition of anonymity because they were not authorized to speak to reporters.

The bill's prospects had improved late Thursday after an intervention by U.S. Secretary of State Condoleezza Rice, who called the powerful chairman of the House of Representatives' Foreign Affairs Committee, Democratic Rep. Howard Berman, according to his office. After the phone call, Berman replaced a bill that was at odds with the Senate counterpart with a matching version.

The bill was expected to pass the House of Representatives Friday. However, time was running short as lawmakers prepare to wrap up this year's session within days to campaign for November's elections. The Senate must pass an identical version to the House and the procedural snag represented a significant hurdle to its passage.

It was unclear who was behind the hold, but five Democratic lawmakers wrote to Senate Majority Leader Harry Reid this month expressing their opposition to the bill.

The setback came after Indian Prime Minister Manmohan Singh tried to rally support in a Washington visit and White House meeting with President George W. Bush. The Bush administration considers the deal a high priority foreign policy goal.

The pact would allow the U.S. to sell nuclear materials to a country that has tested nuclear weapons but has refused to sign international treaties designed to limit the illicit spread of such materials. The accord would reverse three decades of U.S. policy by shipping atomic fuel to India in return for international inspections of India's civilian, but not its military, reactors.

India has faced a nuclear trade ban since its first atomic test in 1974.

The House and the Senate would have to pass the bill and send it to Bush for the deal to go through before a new administration takes office in January. The last-minute attempt comes as Congress debates the bank bailout plan and rushes to pass numerous important measures before shutting down for the year.

This month, the 45-nation Nuclear Suppliers Group of countries that supply nuclear material and technology agreed to lift the ban on civilian nuclear trade with India, the last necessary step before Congress could consider the deal. The ban was imposed because India is not a signatory to the Nuclear Nonproliferation Treaty and has developed nuclear weapons.

The administration has warned that failure to ratify the deal would keep U.S. companies from doing business in India's multibillion-dollar nuclear energy sector.