Former Meghalaya Chief Minister Mukul Sangma on Thursday announced his decision to join the Trinamool Congress, reported ANI.

Earlier on Wednesday, 12 of the 17 Congress MLAs in Meghalaya, including Sangma, had left the party to join the Trinamool Congress, The Shillong Times reported. Meghalaya Assembly Speaker Metbah Lyngdoh said he has received their letters of resignation.

“Congress has failed to play the role of the main Opposition party in the country,” Sangma said at a press briefing in Shillong on Thursday.

Sangma said that he and other MLAs were setting a new trend for the future of the state and the country.

“With utmost sense of humility but complete sense of responsibility and commitment towards fulfilling our responsibility for serving the people, serving the state and serving the nation, we have taken a conscious decision to merge with one of the political parties which all of you know, the All India Trinamool Congress,” he said.

Sangma said he and the other MLAs were failing in their responsibility as the Opposition with the Congress.

Before joining the Trinamool Congress, he had gone to Kolkata to meet election strategist Prashant Kishor but had dubbed it a “courtesy visit”, reported News18. However, at the press conference, Sangma said that he felt he and Kishor shared the “same objective”.

Meanwhile, Congress MP Adhir Ranjan Chowdhury on Thursday claimed that all the states from the North East were conspiring against the party, ANI reported.

“I challenge [West Bengal] Chief Minister Mamata Banerjee to first elect them [Congress MLAs] on her party’s symbol and then formally welcome them to her party,” he said.

Senior Congress leader Mallikarjun Kharge also said that the exit of the 12 MLAs was a conspiracy, the ANI reported. He said that the Congress leadership, including party chief Sonia Gandhi and Rahul Gandhi, were looking into the development.

Kharge, however, added that the Congress will try to come together with other parties to fight the Bharatiya Janata Party in the Parliament.

“We will continue to fight [against BJP] by meeting the people who have always been with us,” he said, adding that the Opposition will rally together against the BJP in the Winter Session of the Parliament.

After the 12 Congress MLAs joined the Trinamool Congress, it became the main Opposition party in 60-member Meghalaya Assembly, the Hindustan Times reported.

Meghalaya is set to have its Assembly elections in 2023.

On Wednesday, Sangma without giving more details about the switch, had said he will share some “happy news and developments” on Thursday, The Indian Express reported.

The former Meghalaya chief minister has reportedly been upset with his party and there has been speculation for months that he would join the Trinamool Congress.

In August, the Congress had appointed MP Vincent Pala as the president of its Meghalaya unit reportedly without Sangma’s consent, according to The Indian Express. Sangma had skipped an event organised for Pala in September.

After that, Congress leaders Sonia Gandhi and Rahul Gandhi met Sangma in October to try to pacify him.

Sangma got involved in the party’s activities – campaigning for the bye-polls held in Meghalaya in October and meeting the Congress’ Meghalaya in-charge Manish Chatrath, general secretary (organisation) KC Venugopal and Pala in November.

Chatrath said told The Indian Express that the meeting on November 18 had been cordial and expressed surprise at Sangma’s decision to quit the Congress. “Sangma also issued a statement after that meeting vowing to strengthen the party,” he added.