Rashtriya Janata Dal chief Lalu Prasad on Sunday remained evasive on retaining the Railways portfolio, even as he announced full support to the United Progressive Alliance in forming a government at the Centre.

Prasad, whose party fared poorly in the recent elections, evaded queries from reporters on whether he would like to return to the cabinet as the railway minister.

"It is not a big thing. Our full support is to the UPA," he told reporters. RJD won only four seats in the Lok Sabha elections as against 24 in the 2004 polls.

While Prasad won from Saran Parliamentary seat, he was defeated in Patliputra by a Janata Dal - United candidate.

Putting up a brave front, Prasad said his party was successful in its mission to 'destroy' the National Democratic Alliance and stop Bharatiya Janata Party [Images] leader L K Advani [Images] from becoming the prime minister of the country.

"We are successful in our mission. Our mission was to destroy the NDA and not let BJP leader L K Advani become the prime minister," he said.

Prasad admitted that it was a mistake not to align with the Congress in the elections in Bihar. "It was a mistake not contesting together in Bihar. Had we fought elections together, we would have got more seats in Bihar," he said.