New Delhi, Jun 14 (IANS): The Left parties Thursday said the Congress has to explain why its two allies announced the name of Prime Minister Manmohan Singh for the president's post and also wondered why the party has not officially named its candidate yet.

The Left parties also said there is no coordination among the United Progressive Alliance (UPA) partners.

"It is unprecedented that the name of a sitting PM has been suggested by the government's own allies for another post. It is for the Congress and UPA to answer. Utter lack of principles binds the UPA allies together," said Communist Party of India-Marxist (CPI-M) leader Brinda Karat.

She said the CPI-M has no role to play till the UPA announces its candidate.

"The question is who is the candidate of the ruling alliance. Why are they not making the name of their candidate public," said Karat.

Communist Party of India (CPI) leader D. Raja said it is for the Congress to answer why its allies Trinamool Congress and Samajwadi Party have named Singh as a candidate for the presidency.

"The Left parties will wait for some more days, consider the situation and see all the names, and will then come out with our decision," said Raja.

He said the Left parties are open for discussion with all parties.

The Left's comments came a day after Trinamool Congress chief Mamata Banerjee, after meeting Congress chief Sonia Gandhi, said the Congress choice of candidates were Finance Minister Pranab Mukherjee and Vice President Hamid Ansari.

However, within an hour Banerjee and Samajwadi Party chief Mulayam Singh Yadav, whose parties are allies of the UPA, announced three different names - of Manmohan Singh, former Lok Sabha speaker Somnath Chatterjee and former president A.P.J. Abdul Kalam, virtually rejecting the Congress choice.