Rashtriya Janata Dal (RJD) chief Lalu Prasad asserted on Saturday that his party would continue the alliance with the Congress and said all Opposition parties must come under the umbrella of the Congress to defeat the BJP across the country.

“The Congress is a big party of this country and the RJD’s alliance with it will continue. All Opposition parties in the country will have to come under the Congress’s banner if they want to defeat the BJP. It’s high time to do so,” Lalu, who has returned to Bihar after three years, told reporters.

“(Congress president) Sonia Gandhi called me recently to enquire about my health. She is my well-wisher. I reminded her that the next general election is going to be held in 2024 and told her that if you want a change then convene a meeting of the leaders of all like-minded parties. She has assured me that she would do so in November,” Lalu added.

The veteran leader’s comments came on a day Trinamul Congress chief Mamata Banerjee said Prime Minister Narendra Modi would become more powerful as the Congress was not serious about politics. Mamata, in Goa to mark her party’s foray in the state, alleged that the country was suffering because the Congress does not take decisions.

Prashant Kishor, the election consultant who guided Mamata’s campaign in the Bengal Assembly elections earlier this year, has been training his guns on Rahul Gandhi and claiming that the Congress had failed to fathom the popularity and strength of the BJP.

Last week AICC Bihar in-charge Bhakta Charan Das had said the Congress had exited the RJD-led Grand Alliance in Bihar and that the national party would go solo in future elections in the state. Das’s announcement had come after the RJD “unilaterally” decided to contest the bypoll to the Kusheshwar Asthan Assembly seat.

Both the RJD and the Congress fielded candidates in Kusheshwar Asthan and Tarapur in the by-elections held on Saturday.

Lalu sought to differentiate between the Bihar Congress and the central unit of the party.

“The Congressmen of Bihar have no concern for the condition of the country. I have talked to Congress president Sonia Gandhi. She and Rahul Gandhi decide about alliances. The future of the Grand Alliance in Bihar is bright,” the former chief minister said, denying that there was any rupture among the Opposition parties in the state.

Lalu asserted that the RJD was going to win both the seats in the bypolls, which he said would pave the way for the end of the NDA regime in Bihar led by chief minister Nitish Kumar.

“I have devised a formula to bring down this government. Nitish’s retirement from politics is certain now,” the RJD chief added.

Lalu said everything was fine between his two legislator sons — Tej Pratap Yadav and Tejashwi Prasad Yadav — but indicated that the latter would lead the party against the backdrop of its stellar performance in last year’s Assembly elections in which “Nitish cheated him of the opportunity to form the government in the state”.

The counting for the Tarapur and Kusheshwar Asthan bypolls will be held on November 2. Around 49.59 per cent votes were polled.