Rice, who had lobbied Congress to approve the deal despite fears it could undercut global efforts to curb the spread of nuclear weapons, had hoped to initial the agreement as the highlight of her brief trip.

However, she told reporters on her plane to New Delhi that the signing had to be delayed because of what she described as bureaucratic rather than substantive issues.

"There are a lot of administrative details that have to be worked out," she said.

The delay is yet another bump in a three-year rollercoaster for the agreement aimed at lifting a ban on US-Indian civilian nuclear trade imposed after India's first nuclear test in 1974.

Rice insisted that her visit should still be seen in the wider context of a budding US-India strategic partnership that covers cooperation on defence, education, the economy, agriculture and other fields.

"The whole purpose of this trip is to move forward, not to look at where we are," she said.

Shortly after landing in New Delhi, Rice held talks with Indian Foreign Minister Pranab Mukherjee and was due to meet Prime Minister Manmohan Singh later in the day.

Both houses of the US Congress voted in favour of the nuclear deal this week, but President George W. Bush has yet to sign it into law.

Rice did not elaborate on the administrative snags that scuppered Saturday's signing, but Indian foreign ministry sources said New Delhi wanted the presidential seal before moving forward.

The deal offers India access to sophisticated US technology and cheap atomic energy in return for New Delhi allowing UN inspections of some of its civilian nuclear facilities.

Military nuclear sites will remain closed to international inspections.

Critics say it undermines global efforts to curb the spread of nuclear weapons, because India has refused to sign the international non-proliferation treaty (NPT).

Rice and other US officials had to lobby hard to win approval for the deal from the International Atomic Energy Agency (IAEA), the UN nuclear watchdog, and the Nuclear Suppliers Group (NSG), which controls global atomic trade.

Daryl Kimball, executive director of the US Arms Control Association and a strong critic of the nuclear pact, said the Indians were probably unhappy with a promise Rice made to Congress in return for its quick adoption.

Rice pledged to push as hard as she can to have the NSG "amend its guidelines to prohibit the transfer of enrichment and reprocessing technology to states that haven't signed the NPT," Kimball said.

India badly wants such technology which can be used for both peaceful and military purposes, Kimball said.

Prime Minister Singh has had a rough ride over the deal at home.

The main opposition Hindu nationalists and the Communists have both slammed it as curbing India's military options and bringing the country's foreign policy too much under US influence.

Even after the accord is signed, US firms cannot do business until New Delhi signs a safeguards agreement with the IAEA.

The US Chamber of Commerce said with India's 34-year nuclear isolation now history, a potential 150 billion dollars of new investments were expected in terms of new nuclear generating capacity by 2030.

The agreement is a key foreign policy success for Bush who agreed to it with Singh in 2005 as part of a strategic partnership between the two biggest democracies.

During her talks in India, Rice said she would also discuss India's support for boosting Afghan political and economic institutions as part of efforts to integrate Afghanistan into a broader south and central Asian economy.

She was scheduled to leave for Kazakhstan on Sunday.

Related Links
Nuclear Power News - Nuclear Science, Nuclear Technology
Powering The World in the 21st Century at Energy-Daily.com

Memory Foam Mattress Review

SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News