Ashwini Choubey allegedly spoke to the police officer "in a very aggressive tone".

A union minister has been charged with threatening a police officer in Bihar, which the BJP rules in alliance with Nitish Kumar's Janata Dal United. Ashwini Choubey, a BJP leader and minister of state for health in the central government, has not been spared after he allegedly shouted at a police officer on Monday.

The police in Buxar, where the incident took place, have accused the minister of intimidating an officer on duty and humiliating him in full public glare.

Mr Choubey reportedly berated a Station House Officer Rajiv Ranjan for naming a BJP worker in the "Goonda register", which is a list of potential trouble-makers required to furnish a guarantee of good conduct.. This happened during his "Janata Durbar" or public hearing at his constituency.

The minister allegedly spoke to the police officer "in a very aggressive tone" and said: "Does he look like a goonda to you? Have you ever seen a goonda? You better mend your ways or I will strip you of your uniform."

The police say the BJP worker at the core of the incident, Laxman Dubey, has been on the offenders' register for some time and was charge-sheeted in a case of violation of prohibitory orders.

That such a complaint against a central minister has been filed by the Bihar police is seen as an indicator that Chief Minister Nitish Kumar does not plan to intervene on behalf of BJP leaders.

Mr Choubey defended himself, saying all he wanted to tell the police was that innocent people were being branded as criminals. "There was confusion. Police officers were not able to tell us anything properly. Those who have been declared criminals are farmers and BJP workers. I said to the police officer that an FIR should be registered on time and innocent people should not be given the tag of a criminal," he said.

Earlier, another Union Minister, Giriraj Singh, failed to get the desired response when he pulled up a Bihar official in his parliamentary constituency Begusarai for slow pace of flood relief. Mr Singh even dramatically remarked that he "felt like committing suicide" when he saw the state of the flood-hit people.

To which, a Janata Dal United Chief spokesman, Sanjay Singh, snarked: "Who has stopped him?"

Sources say in these controversies, it is clear that Nitish Kumar is unlikely to step in and has decided to back state government officials against BJP ministers.