The Communist Party of India on Saturday said it was against 'tainted' persons holding ministerial positions but maintained that the formation of the Union Council of Ministers is the prerogative of the prime minister.

"My party certainly does not want tainted ministers to be there, but I am not in the act of forming government," party general secretary A B Bardhan said in a debate on NDTV.

"The concerned parties, which are part of the government, also have a responsibility," CPI national secretary D Raja said adding that the Left parties, which are supporting the United Progressive Alliance government from outside, had taken a 'principled position' in this regard.

When approached for comments, Union Steel Minister Ram Vilas Paswan evaded a direct reply saying that it was the prime minister's prerogative to appoint ministers.

Also Read PM defends tainted ministers BJP to target chargesheeted ministers

Meanwhile, the Janata Dal (United) has threatened an indefinite agitation from Monday to demand ouster of 'tainted' ministers from the Manmohan Singh government.