Millions of Indians have cast their ballots in country's biggest day of general election to choose the next parliament, with the ruling Congress party struggling to hold ground against the Hindu nationalist opposition Bharatya Janta Party.

More than 65 percent of the nearly 200 million eligible voters turned up on Thursday to exercise their franchise, with eastern West Bengal state registering about 80 percent voting, while about 67 percent came out to vote in southern Karnataka state - home to India's software hub.

The politically crucial Uttar Pradesh state witnessed 56 percent voter turnout, while the Maoist-hit regions of Jharkhand registered about 60 percent turnout.

The fifth phase of voting was conducted in 121 constituencies across 12 states, including northeastern state of Manipur and Indian-administered Kashmir, which saw 74 percent and 69 percent polling respectively.

"We want Modi to win this time. That's why we are here early in the morning, doing our best for him," said Preetham Prabhu, a 32-year-old software engineer who was the first to cast his vote in a polling station in a residential suburb of Bangalore.

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Officials had been deployed on Wednesday at thousands of polling booths where they checked voter documents in several constituencies.

"You can see that all the preparations to keep the elections fair, free, transparent and error-free are done," said District Commissioner of Doda district in Jammu and Kashmir, Mubarak Singh.

Security was beefed up and paramilitary forces set up as some of the most threatened states get set to vote, including the violence-affected Indian-administered Kashmir and the recently riot-hit state of Uttar Pradesh.

Bharat Tamang, a voter in eastern Darjeeling town, told Al Jazeera: "Earlier we voted for our leaders but this time we have voted for our identity."

BJP favoured

The election has turned into a face-off between Rahul Gandhi and Narendra Modi, who has been lauded by Indian corporate leaders and foreign companies for his business-friendly policies.

Modi is Chief Minister of Gujarat, which witnessed one of India's worst anti-Muslim riots in 2002.

Modi's Hindu nationalist Bharatiya Janata Party (BJP) opposition party and its allies are expected to win a narrow majority, defeating the ruling Congress party, in the world's largest democratic election, the latest opinion poll showed on Monday.

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The BJP and its allies have until now been forecast to win the largest chunk of the 543 parliamentary seats, but fall short of the 272-seat mark needed for a majority.

The Congress party, led by the Nehru-Gandhi dynasty, and its allies were forecast to win just 111 seats.

Congress faces a struggle to be re-elected after a decade in power due to public anger over the economic slowdown, high inflation and a string of corruption scandals.

Voter turnout has averaged 68 percent so far, the Election Commission said on Wednesday, versus 58 percent across the whole election in 2009.

Source: Al Jazeera and agencies