Congress chief Sonia Gandhi will head a six-member United Progressive Alliance -Samajwadi Party Coordination Committee constituted on Saturday.
The committee has Prime Minister Manmohan Singh, External Affairs Minister Pranab Mukherjee and Defence Minister A K Antony as its members.
Two members to the committee will be nominated by the Samajwadi Party, said All India Congress Committee spokesman Manish Tewari.
There have been reports that SP General Secretary Amar Singh and party chief Mulayam Singh Yadav would be representing the party but there has not been any official word so far.
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The constitution of the Committee indicates that the SP, like the Left, would support the government from outside. The development also suggests that they would exert influence like that of the Left.
The announcement of the committee came exactly a month after the Manmohan Singh government won the trust vote with the crucial support of SP after the withdrawal of Left parties.
A similar arrangement existed between the UPA and Left parties to ensure smooth coordination between the government and the ruling alliance on one side and the key outside supporters on the other.
The UPA and the Left, however, parted ways last month on the nuclear deal issue following which the SP filled the key slot ensuring the survival of the government.
Price for Samajwadi support = Oust Mayawati
The Congress and the SP are also trying to arrive at a seat sharing deal in Uttar Pradesh where the main rival of both parties is the Mayawati-led Bahujan Samaj Party. The talks between the two sides on the issue are expected to start soon.