Left-wing parties in India have launched a national campaign against a controversial India-US nuclear deal, reports BBC.
The communists stopped supporting the government last week in protest at its decision to push ahead with the deal to meet India's soaring energy needs.
The governing coalition, which has now been reduced to a minority, will seek a vote of confidence on 22 July.
If the government loses the vote, India faces early elections and the nuclear deal would probably be scuttled.
Under the accord, India would gain access to US civilian nuclear technology and fuel in return for opening civilian nuclear facilities to inspection. Nuclear weapons sites would remain off-limits.
The communists fear the accord could give the US too much influence over Indian foreign and nuclear policy.
"We cannot support a government that is undermining our independent foreign policy," senior communist leader Prakash Karat said, addressing a meeting of supporters in the capital, Delhi.
"The government's priority is to enter into the nuclear deal and not to solve the economic crisis that the nation is facing."
Several left-wing leaders who addressed the rally criticised the government for its "obsession" with the nuclear deal. The government was also criticised for rising prices and the high rate of inflation. Left leaders say they will explain to the people the reason they stopped backing the Congress party-led coalition and why they oppose the nuclear deal.
Senior left leader AB Bardhan said meetings would be organised in towns and villages across the country as part of their campaign against the deal.
The campaign is due to go on until the end of August.
A two-day special session of the lower house of Indian parliament - the Lok Sabha - will be convened on 21 July, with the confidence vote scheduled for the following day.
The Congress party hopes a deal with the regional Samajwadi Party will make up for the loss of support from the communists in parliament.
But correspondents say the government has a tough fight on its hands. A defeat for the government in the 543-member lower house would trigger an early election, and almost certainly mean the end of the nuclear pact with the US. India is under pressure from Washington to sign the accord before the US presidential elections in November.
Critics of the deal fear assistance to India's civil programme could free-up additional radioactive material for bomb-making purposes.
