"Narendra Modi seems a PM candidate of foreigners due to which America, UK and other western countries are softening their approach towards him in recent days," Prasad said.
"He will not be able to fulfil his dream (of being the PM)..if he becomes PM he will trigger communal riots in the country," Prasad said.
Prasad was talking to reporters after a RJD meeting of MLAs, MLCs and state office bearers in regard to a party rally at Patna in May.
On Modi calling Congress as "termite" at the BJP's national executive meeting at Delhi, Prasad said "Modi himself is termite. The BJP and RSS are termites which are eating up secular tree of the country."
Prasad, who has served as Railway minister in the UPA I, claimed that secular parties would form government at the centre after 2014 parliamentary elections.
On Pakistan Prime Minister Raja Pervez Ashraf paying a visit to Ajmer, he said that Ashraf was welcome to perform ziyarat but the country would continue to protest the beheading of Indian soldiers by Pakistani army.
On Prime Minister Manmohan Singh praising Nitish Kumar's rule for remarkable growth rate, the RJD chief said "this reflects his greatness and by doing so he has demonstrated his respect for federal structure of the country."
Referring to JD(U) sponsored rally at Delhi on March 17 in support of demand for special category state for Bihar, Prasad remarked "Nitish Kumar is befooling people."