Nitish Kumar has made it clear that he has no problem if Prashant Kishor goes or stays. (File)

As the Nitish Kumar-Prashant Kishor fight boils over in Bihar's ruling Janata Dal United (JDU), a party leader has added to the spiraling feud by comparing Mr Kishor to the deadly Coronavirus.

In a vitriolic attack, JDU leader Ajay Alok has also said the master poll strategist, who became the party's number two after Nitish Kumar soon after joining it in 2018, was "not trustworthy".

"This man is not trustworthy. He could not win the trust of (Prime Minister Narendra Modi ji and Nitish ji. He works for AAP, talks to Rahul Gandhi, sits with Mamata didi (Mamata Banerjee). Who will trust him? We are happy this #coronavirus is leaving us, he can go wherever he wants to," said Ajay Alok, a former party spokesperson, in an unfiltered attack.

The JDU has distanced itself from the comment. A senior leader, Vashishta Narayan Singh, asserted that Ajay Alok was no longer spokesperson so the comments do not reflect the party's thinking.

But JDU chief Nitish Kumar, the Chief Minister of Bihar, betrayed his fury at Mr Kishor yesterday when he made it clear that he had no problem whether he quit or stayed. He also said if Mr Kishor did stay, he would have to fall in line.

Last month, their break-up over the citizenship law CAA was averted at the last minute when Nitish Kumar turned down his resignation at a party meet.

Since then, Mr Kishor has sharpened his public digs at Mr Kumar and challenged him to take a firm stand against the Citizenship (Amendment) Act pushed by ally BJP.

This time, the sparring has gone south with the Chief Minister caustically reminding Mr Kishor that he had inducted him into the JDU at BJP leader Amit Shah's instance. Mr Kishor's response was quick and brutal.

"What a fall for you to lie about how and why you made me join JDU!! Poor attempt on your part to try and make my colour same as yours! And if you are telling the truth who would believe that you still have courage not to listen to someone recommended by Amit Shah," tweeted the JDU vice president.

Mr Kumar had first made the startling claim about Amit Shah's recommendation in an interview to a private television 14 months ago. Sources close to Mr Kishor said the comment was in poor taste as just two days ago he raised objections to private conversations being referred to in a letter written by Pavan Verma.