Prime Minister Narendra Modi will address four election rallies in Bengal on Sunday, the back-to-back events on the same day indicating how crucial the state is for the BJP in this general election.

Modi, who has already addressed a dozen campaign rallies in Bengal this poll season since his first on March 1 in Arambagh, will be at Barrackpore in North 24-Parganas, Panchla in Howrah and Chinsurah and Pursurah in Hooghly on Sunday.

While Panchla is under the Uluberia Lok Sabha constituency, Chinsurah and Pursurah are part of the Hooghly and Arambagh Lok Sabha constituencies, respectively.

"Though Modi ji has already addressed 12 rallies in Bengal, four rallies by him on a day is unprecedented.... It is a clear hint that the party is hopeful about improving its tally (from 18 in 2019) in Bengal," said a BJP leader.

Modi arrived in Calcutta on Saturday evening and headed to Raj Bhavan to spend the night. His first rally is at Barrackpore at 11.30am on Sunday.

Multiple sources in the BJP said that they were looking forward to Sunday's events with keen interest as it would be his first outing in the state since the videos on Sandeshkhali — with which Trinamool has challenged the BJP's narrative of sexual abuse and rapes of women on the island — surfaced.

Trinamool will also closely track the contents of Modi's address as Union home minister Amit Shah, in his poll rallies, maintained silence on the purported videos that alleged that the BJP had "scripted" the "fake Sandeshkhali complaints".

Trinamool insiders think that the BJP's plan to create hype around Sandeshkhali suffered a jolt after the videos surfaced. They also said the molestation charge against governor C.V. Ananda Bose and the Supreme Court's interim stay on the cancellation of appointments of 25,753 teachers also dealt a blow to the BJP in Bengal in this crucial election.

"As his party lost momentum in Bengal because of these developments, the prime minister is likely to try and cover up the misdeeds of his colleagues in Bengal, who manufactured the Sandeshkhali issue out of nothing.... We saw how Amit Shah maintained silence on the videos that revealed the truth in Sandeshkhali. We want to see if the PM speaks on the issue or follows the same line as Shah," said Bengal industries minister Shashi Panja.

The Bengal minister also claimed that the BJP was trying to focus on Bengal as north, west and south India would not yield as many seats as the saffron camp had expected.

"Now the BJP will be desperate to get extra seats from Bengal, which they won't get," she added.

BJP leaders said that Trinamool should not expect the so-called videos on Sandeshkhali or charges against the governor to impact the ongoing Lok Sabha election.

"Trinamool is already rattled and will not get seats in two digits. It is unfortunate that a leader like Mamata Banerjee has now left the political battle and is resorting to petty issues like viral videos and others," said Samik Bhattacharya, the BJP's chief spokesperson in Bengal.