NEW DELHI : A landmine blast blamed on Maoist rebels killed seven police officers on Sunday in an insurgency-hit region of central India, the latest deadly attack during national elections, an official said.The policemen were patrolling a densely forested area of Maharashtra state when their vehicle hit the mine planted by rebels, amid tight security as the elections draw to a close, a local police officer said. ‘The team was travelling from one part of the region to another when a landmine blast hit their vehicle,’ Dharmendra Joshi, police public relations officer for Gadchiroli district where the attack occurred, told AFP.‘Seven of our men have lost their lives and two others, who are seriously injured, have been airlifted to Nagpur (city) for treatment,’ he said. The officer said teams have been posted to the Maoist-hit region to ensure ‘peace and calm’ ahead of vote counting across the country after the final round of polling on Monday.‘Our police teams have been on high alert and have been posted in different villages in this Naxal-affected region to ensure peace and calm in the lead up to May 16 election counting,’ he said, referring to the rebels also known as Naxalites. ‘An operation has been launched to track the men behind this attack and the entire area has been cordoned off,’ he added.The Maoist rebels have called for a boycott of the mammoth election which ends on Monday, with the last round of voting in three states. The opposition Hindu nationalist Bharatiya Janata Party (BJP) is expected to vault to power over the ruling Congress party when votes are counted and results announced on May 16, four days after Monday’s polling. Maoist rebels killed five police officers and three polling officials in April as they were returning from polling duty in Jharkhand state.Insurgents also killed 14 people in two poll-related blasts in the central state of Chhattisgarh in March. Separatist and Maoist insurgencies affect large swathes of India’s northeast, northwest and central regions. Many of the rebels say they are fighting authorities for land, jobs and other rights for poor tribal groups. The Maoist insurgency has cost thousands of lives. The rebels are believed to be present in at least 20 states but are most active in forested, resource-rich areas in the states of Chhattisgarh, Orissa, Bihar, Jharkhand and Maharashtra.