NEW DELHI -- At least 11 people have been injured in clashes between the ruling and main opposition parties in the eastern Indian state of West Bengal where local civic body polls began this morning amid tight security, a senior police official said.

"The clashes took place between the ruling Trinamool Congress party and the main opposition Communist Party-led Left Front at Sabong in the state's West Midnapore district. The injured included supporters of both the political parties. They have been admitted to a local hospital," he said, on condition of anonymity.

Three left-wing Naxalite-dominated districts of the state -- West Midnapore, Bankura and Purulia -- went to the first of the five-phased local civic body polls Thursday. Para-military troopers have been deployed to keep a vigil on every poll booth so as to ensure smooth voting in the three districts.

The poll began after the country's Supreme Court recently fixed the dates following a bitter tussle between the West Bengal government and the independent state Election Commission who were fighting on a number of issues, including the primacy to conduct the polls, election dates and the security arrangements.

The next four phases of the polls are due on July 15, 19, 22 and 25.

The local civic bodies are actually a three-tier panchayat system of the state, considered a model for the rural development system in the country.