WASHINGTON, Dec 11: US President George W. Bush had not signed the Indo-US nuclear deal till late Monday afternoon, causing speculations that last minute differences with India could delay the signing.

Mr Bush was scheduled to sign the US-India Peaceful Atomic Energy Cooperation Act of 2006 into law early Monday and the White House had already issued a statement praising Congress for passing the bill.

US officials, when asked for comments, said the president was likely to sign it late Monday but diplomatic sources said that last minute differences between India and the United States had delayed the signing.

In India, opposition parties as well as some in the ruling alliance have described some of the conditions retained in the final version of the bill as “humiliating” and urged the government to reject them.

The opposition Bharatiya Janata Party has decided to fight the deal in the Indian parliament, with strong backing from India’s influential nuclear scientists.

Some left-wing parties in the ruling alliance are also opposing the deal and have threatened to abstain in the parliamentary vote.

The opposition claims that the main purpose of the deal is to limit India’s nuclear weapons programme by subjecting it to highly intrusive inspections and effectively banning future Indian nuclear tests.