Agartala, Sep 5 : Amid heavy security, polling for the by-elections in Tripura's two Assembly constituencies of Boxanagar and Dhanpur is underway on Tuesday with over 40 per cent voter turnout recorded in the first four hours of balloting. Police said that there is no untoward incident reported from anywhere of the two Assembly segments under the Sepahijala district. Men and women in large numbers queued up in front of polling stations before polling began at 7 a.m. Voting will conclude at 4 p.m. without any break. In all, 93,495 voters, including 45, 222 female electorate, are eligible to cast their votes in 110 polling stations to decide the electoral fortune of eight candidates, four each in two seats. The CPI-M state Secretary Jitendra Choudhury claimed that due to the threats and intimidations of the ruling BJP cadres the party's polling agents could not attend in more than 50 per cent of the 110 polling stations in the two seats. The ruling party, however, denied the accusations. For the first time in over five years, a direct contest is being witnessed between the ruling BJP and the opposition CPI-M-led Left Front. The Congress and the Tipra Motha Party (TMP), the other two main opposition parties in the state, had announced not to field candidates in the two seats to prevent division of vote share. However, leaders of the TMP headed by Pradyot Bikram Manikya Deb Barman declared not to support the BJP or the CPI-M in the by-elections, leaving the choice to the voters and party workers. Congress leaders, including state party President Asish Kumar Saha, MLAs Sudip Roy Barman have campaigned for the CPI-M candidates. Talking to IANS, Saha said that to defeat the BJP and to ensure victory for the opposition INDIA alliance, they have campaigned in both the Assembly segments for the Left nominees. After the formation of INDIA, Tuesday's by-elections will be its first electoral battle. According to political observers, the bypolls are an acid test for the ruling BJP, as the chances of division of opposition votes are negligible. The CPI-M has nominated Mizan Hossain in Boxanagar and Kaushik Chanda in Dhanpur, while the ruling BJP has fielded Taffajal Hossain in Boxanagar and Bindu Debnath in Dhanpur. CPI-M's Mizan Hossain and BJP's Bindu Debnath are contesting elections for the first time, while Kaushik Chanda and Taffajal Hossain had contested the Assembly polls held in February this year. In the February 16 Assembly polls, the Left parties and the Congress had contested the elections together with seat-sharing arrangements, while the TMP went alone. The by-election in the Dhanpur Assembly seat was necessitated after Union Minister Pratima Bhoumik resigned from the Assembly, days after her election from the seat as a BJP nominee. The Muslim-dominated Boxanagar Assembly seat fell vacant after the death of sitting CPI-M MLA Samsul Haque, who died on July 19 after a cardiac attack. /IANS