The move was made hours after Nitish Kumar took oath as the chief minister of the Grand Alliance.
Bihar's new ruling coalition, Mahagathbandhan (Grand Alliance), on Wednesday brought a no-confidence motion against Assembly Speaker Vijay Kumar Sinha who is a BJP MLA, a senior JD(U) leader said.
A notice signed by several legislators of the Grand Alliance was submitted to the Assembly secretariat.
The move was made hours after Nitish Kumar took oath as the chief minister of the Grand Alliance.
"The motion against Mr Sinha will be taken up by the House when it meets to enable Nitish Kumar to move a trust vote," senior JD(U) leader Vijay Kumar Chaudhary said.
A special session of the Assembly is expected to be called either on August 24 or 25.
According to the rule, a Speaker can be removed from office by a resolution of the Assembly passed by a majority," said Mr Choudhary.
While constituents of the Mahagathbandhan have a total of 164 members in the Assembly, the BJP has 77 MLAs.
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