Patna, Sep 21 (IANS): The new combine of Bihar's ruling Janata Dal (United), the Rashtriya Janata Dal and the Congress is throwing a big challenge for the Bharatiya Janata Party, two senior state BJP leaders said here Sunday.

"The party (BJP) should not treat the JD-U, the RJD and the Congress combine lightly. It is a big challenge for the party," said Shatrughan Sinha, who is a Lok Sabha member of the BJP from Patna Saheb.

Former union minister and BJP national vice-president C.P. Thakur said it was a matter of worry for the party after the JD-U, the RJD and the Congress joined hands in the state. "We should be careful of this new combine," he said.

Both Sinha and Thakur said rivals should not be treated as weak in politics and the party should review its strategy to take on the new combination.

Sinha and Thakur also stressed on collective leadership instead of reliance on one-man show for the party in the next assembly polls in the state due in 2015.

It is for the first time that BJP leaders publicly underlined challenges from the new combine.

Political analysts here said infighting in the BJP's state unit surfaced after the party's defeat in last month's by-polls to 10 assembly seats. The new combine of the JD-U, the RJD and the Congress won six of the 10 seats that were at stake.

Besides, some senior party leaders openly opposed the projection of former deputy chief minister Sushil Kumar Modi's as chief ministerial candidate while arguing that there are several faces in the party for the top post.