JD(U) president Nitish Kumar on Sunday took oath as Chief Minister of Bihar for a record ninth time after a dramatic volte-face, ditching the Mahagathbandhan and the opposition bloc INDIA and forming a new government with the BJP, which he had dumped less than 18 months ago.

Nitish was sworn in by Bihar Governor Rajendra Arlekar at Raj Bhavan in the presence of senior leaders including BJP national president J P Nadda, hours after he resigned from the post, saying "things were not working well" for him in the Grand Alliance and the opposition bloc.

BJP leaders -- Samrat Choudhary and former Speaker Vijay Kumar Sinha- were among those who took oath of office. The two are named as Deputy Chief Ministers.

Earlier, Choudhary and Sinha were named as leader and deputy leader, respectively, of the BJP legislature party. They thanked the party's top leadership for the opportunity and vowed to "protect Bihar from the jungle raj unleashed by Lalu Prasad's RJD".

JD(U) members Vijay Kumar Choudhary, Vijendra Yadav and Shrawan Kumar also took oath apart from former CM Jitan Ram Manjhi-led Hindustan Awam Morcha's Santosh Kumar Suman and independent legislator Sumit Singh.

Congratulating Nitish and his two deputies, Prime Minister Narendra Modi asserted that the newly sworn-in NDA government in Bihar will leave no stone unturned for the state's development and to fulfil people's aspirations.

In a post on X, Modi said he is confident that the new government in Bihar will serve the people with full dedication.

Notably, no leader of the RJD, the single largest party in the assembly, was present at the ceremony.

Prasad's son Tejashwi Yadav, who was the Deputy CM until Kumar walked out of the alliance, said:"The JD(U) will be destroyed in the upcoming assembly polls".

"The game is not over for us. The game has just begun", said the young leader.

His elder brother Tej Pratap Yadav, also a former minister, and Singapore-based elder sister Rohini Acharya came out with a flurry of posts on X, lampooning the JD(U) president, whom they likened to a "chameleon".

The CPI(ML) Liberation, which supported the Mahagathbandhan government from the outside, launched a blistering attack on Kumar, accusing him of "betrayal".

In an acerbic Facebook post, the party's general secretary Dipankar Bhattacharya alleged that Kumar, "who has had the longest stint as CM", will be used by the RSS-BJP combine "as its pawn".

Political strategist turned politician Prashant Kishor also took a swipe at Kumar, saying:"Switching sides has become part of his politics" and added that the BJP might end up paying "a huge price" for supporting the JD(U) chief who had ditched it in August 2020.

Earlier, Kumar, after submitting his resignation, had told reporters "The government that was in place now comes to an end. I have let it go".

The 72-year-old leader indicated that he was not feeling happy with the way things were in the Mahagathbandhan in the state as well as the INDIA bloc that he helped take shape but which failed to adequately recognise his efforts.

"You all know how I came to this alliance and also how I worked to bring together so many parties. But of late things were not working well. It was not going down well with those in my party as well", said Kumar.

He also made an indirect reference to the deafening silence he had maintained over the political turmoil that had engulfed the state for the past few days, leaving his allies wondering about his current move.

Kumar had resigned after a meeting of the JD(U) legislature party, which authorised him to take any decision about the alliance.

Kumar had joined the Mahagathbandhan in August 2022, when he had snapped ties with the BJP accusing it of trying to "split" his JD(U). He formed a new government with a multi-party coalition that included RJD and Congress.

Kumar had first taken oath as the state's Chief Minister in 2000. However, his government fell within a week. He again became CM in 2005 and also returned to power five years later.

After his breakup with BJP in 2013, Kumar still survived in power as the JD(U), which was then just a few members short of the majority mark, got outside support from parties like Congress and CPI, besides a disgruntled faction of the RJD.

A year later, though, he stepped down owing moral responsibility for the JD(U)’s drubbing in Lok Sabha elections.

In less than a year, he was back as Chief Minister, elbowing out his rebellious protege Jitan Ram Manjhi, this time armed with ample support from the RJD and the Congress.

The Grand Alliance that came into being with JD(U), Congress and RJD coming together, won the 2015 assembly polls handsomely but came apart in just two years.

Kumar returned to the NDA in 2017, hoping to get some traction after taking a stand against corruption taint on his then deputy Tejashwi Yadav.

In the current 243-member Bihar Assembly, JD(U) has 44 MLAs and the BJP 78. Kumar also has the support of one Independent member. Jitan Ram Manjhi-led Hindustani Awam Morcha, which is already a part of the NDA, has four MLAs.

The RJD (79) along with the Congress (19) and the Left parties (16) have a combined 114 MLAs, eight short of a majority.