RLSP leader Upendra Kushwaha, who quit the Modi government this month, joined the United Progressive Alliance (UPA) at the AICC headquarters in the presence of RJD leader Tejashwi Yadav, Loktantrik Janata Dal leader Sharad Yadav, Hindustani Awam Morcha Jitan Ram Manjhi and Congress Treasurer Ahmed Patel.

Addressing the media, Kushwaha said he had been consistently raising issues of social justice but an attempt was made to weaken his party by Bihar Chief Minister Nitish Kumar who he said got "strength" from Delhi, an apparent reference to the BJP.

"Nitish Kumar is a big conspirator. He got help from Delhi government. He decided that Kushwaha has to be demolished so that he will not be able to take up the issues of Bihar," he said.

Kushwaha also said that Prime Minister Narendra Modi had promised during the 2014 election campaign that he would address the issues of education, jobs and healthcare for the people of Bihar.

But on all fronts, he failed to fulfil his promises. There was a difference between his talk and action. "I never believed there could be so much difference," he said.

Kushwaha went on to praise Congress President Rahul Gandhi in the manner he promised loan waiver for farmers in Madhya Pradesh, Rajasthan and Chhattisgarh and the "first step" was the writing off of the loans.

Tejashwi Yadav said the BJP has lost allies in the north, west, south and east of the country and a "mahagatbandhan" (Grand Alliance) across India was in the making against the BJP-led National Democratic Alliance (NDA).

He too praised Rahul Gandhi saying he had implemented what he had promised and was patiently building up an opposition coalition.