Kolkata, November 25: About 30.17 per cent of over seven lakh electorate on Monday exercised their franchise in the by-polls to three Assembly seats in West Bengal till 11 am, an EC official said.

Kharagpur Sadar Assembly constituency, having 2.25 lakh voters, registered 28 per cent polling in the first four hours, the official said. Both Kaliaganj with 2.69 electors, and Karimpur with 2.4 lakh electorate recorded 31.25 per cent votes, he said.

Voting is underway in 801 polling stations of the three constituencies amid strict security arrangements. Over seven lakh people are eligible to decide the fate of 18 candidates in the three constituencies.

In Karimpur Assembly seat, Trinamool Congress (TMC) supporters raised 'go back' slogans when BJP candidate and vice-president of the West Bengal unit of the party, Jay Prakash Majumdar tried to enter a booth. The police resorted to baton charge to disperse the mob. Local TMC leaders accused Majumdar of vitiating the peaceful atmosphere.

In Kaliaganj constituency, BJP candidate Kamal Chandra Sarkar was seen helping his wife to cast her vote. The TMC has lodged a complaint with the Election Commission and the poll panel said, it is looking into the allegation.

Two of the three Assembly constituencies - Kharagpur Sadar and Karimpur - fell vacant post general election as the sitting MLAs contested and won Lok Sabha seats. By-polls were necessitated in Kaliaganj following the death of Congress MLA Parmathanath Roy.

Congress nominee Dhitashree Roy, supported by the CPI (M), is pitted against TMC's Tapan Deb Sinha and BJP's Kamal Chandra Sarkar in Kaliaganj. In Karimpur, vacated by MLA Mahua Moitra after emerging victorious from Krishnnanagar Lok Sabha seat, the CPI(M)-Congress candidate Gholam Rabbi is contesting against BJP's Jay Prakash Majumdar and TMC's Bimalendu Singha Roy.

Prem Chandra Jha of the BJP is pitted against Chittaranjan Mandal of the Congress-CPI(M) alliance and Pradip Sarkar of the TMC in Kharagpur Sadar Assembly seat - vacated by MLA Dilip Ghosh after winning Medinipur Lok Sabha seat.

The by-polls are expected to be a litmus test for the ruling Trinamool Congress (TMC) and the BJP - which emerged as a main opposition in the state after the Lok Sabha polls earlier this year - ahead of 2021 state elections.

The Congress and the CPI(M-led Left Front, which have been pushed to distant third and fourth in the state, are contesting the by-polls after entering into an electoral alliance. The results will be declared on November 28.