New Delhi - A crucial two-day session of the Indian parliament to take up a vote of confidence in the United Progressive Alliance government began Monday with the prime minister expressing confidence that his coalition will prevail. 

Prime Minister Manmohan Singh was forced to call the trust vote after his communist partners withdrew parliamentary support from the Congres-party led alliance, in protest against a civilian nuclear deal with the United States which they said compromised on India's strategic sovereignty. 

The debate is scheduled to continue until Tuesday evening when the floor vote will be called. 

Singh flashed the victory V-sign as he entered the Parliament House complex shortly before the house convened for the debate. 

"We will prove the majority on the floor of the house," Singh told reporters. 

Singh later opened the debate and moved the confidence motion in the parliament. 

The government needs 272 of the 542 members to survive the vote of confidence. 

Indian news channels and newspapers said the government and the opposition were counting their numbers until Monday and predicted the vote would be close. 

The NDTV news channel reported that the UPA had a slight edge and would get the required number of votes. 

The daily Times of India said the government would garner 268 definite votes, the opposition 270 and four lawmakers undecided. 

The Hindustan Times newspaper projected the UPA would get 270 out of the 272 votes needed and the opposition 266, with seven undecided or abstaining. 

A defeat for the UPA would trigger political uncertainty in the country that faces slower economic growth rate and double-digit inflation. It would also spell the death of the nuclear deal. 

The UPA government is scheduled to complete its five-year term in May 2009, but failing the floor test could mean early elections, perhaps in November-December, or a new coalition government. 

The government argued that the nuclear pact with the US is crucial for country to bridge its energy deficit and maintaining its high economic growth. 

Under the nuclear agreement, the US would provide India fissile material and technology for civilian reactors, ending a three-decade ban. India would in turn, open its civilian nuclear reactors to international inspections. (dpa)