Millions of Indians voted in the third phase of elections that are crucial to the main opposition Hindu nationalist party's bid to end the 10-year rule of the Congress party.
Violence broke out at several constituencies Thursday. A bomb set off by suspected Maoist rebels killed two Indian soldiers and wounded at least three in eastern Bihar state.
Maoist insurgents have urged voters to stay away from the polls and threatened to disrupt the election.
The multi-phase parliamentary elections are spread out over a month to give more than 800 million registered voters the chance to cast ballots.
Nearly 110 million people were eligible to vote Thursday in constituencies in 11 Indian states and three federally administered union territories.
The Hindu nationalist opposition party, BJP, is looking to push out the Congress party, promising to revitalize a stagnant economy.
Outgoing Prime Minister Manmohan Singh has said it would be a disaster if the BJP's Narendra Modi becomes the new prime minister.
India's Supreme Court cleared Modi of charges of inciting Hindu-Muslim riots in Gujarat state in 2002 that killed around 1,000 people.
The last day of the elections is May 12.