New Delhi - India's left-wing parties Monday launched a nationwide campaign explaining their withdrawal of support to the United Progressive Alliance (UPA) government over a controversial civilian nuclear deal with the United States.

Addressing a public rally in the Indian capital, senior members of the four left parties alleged the UPA government failed to keep its electoral promises due to its "obsession" with the nuclear deal, IANS news agency reported.

The campaign was aimed at explaining to how the UPA's pro-US policies were harmful to India's economic and strategic interests, Prakash Karat, General Secretary of the Communist Party of India-Marxist (CPI-M), said at a press briefing.

The CPI-M, along with the Communist Party of India, the Forward Bloc and Revolutionary Socialist Party of India withdrew support to the UPA government last week.

Thir 59 lawmakers have provided crucial support to Prime Minister Manmohan Singh's minority UPA government over the past four years.

Singh is to face a confidence vote in parliament on July 22, which he hopes to win the support of the regional Samajwadi Party and other smaller parties.

If the government loses the vote, India could face an early election with the nuclear deal likely to be shelved.

During the month-long campaign, left party leaders are to travel across the country explaining their view and present alternatives to meet India's growing energy needs for development.

The UPA government's policies were not in the interest of farmers, rural poor and workers, Karat said.

The government and Singh's Congress Party wanted to keep their promise to US President George W Bush, he added.

"It is their primary aim and not tackling inflation or price rise," Karat said. "The nuclear deal and price rise are the issues on which we withdrew support."

India's inflation, linked to a wholesale price index, was at 11.89 per cent on Friday, the highest since April 1995. Analysts said rising crude oil and global commodity prices will keep inflation in the double digits over the next few months.

The UPA government maintains the nuclear deal is needed to meet India's growing energy needs if it wants to keep up its current growth rate of about 9 per cent per year.

Under the nuclear agreement, the US would provide India fissile material and technology for civilian reactors which India would open to international inspection. (dpa)