Modi accused of breaking India's election rules by taking selfie

The chief minister of Gujarat and leader of the Hindu nationalist BJP party, voting as nine of the country's 29 states went to the polls, took a photograph of himself holding a lotus flower in his inked finger after casting his ballot.

Angry supporters of the ruling Congress party complained to the authorities that Modi had flouted election law by canvassing for votes in violation of rules forbidding campaigning on election day. Gujarat police chief PC Thakur said a preliminary case was launched against Modi at the request of the election commission.

Maximum punishment for violating the rule is two years imprisonment, although Modi is unlikely to be charged. Politicians in India routinely face criminal cases which rarely reach the courts.

Congress and the BJP are locked in a tense battle for control of the next national government, with Congress facing a possible drubbing over corruption scandals and a recent economic slowdown.

In his speech after voting, Modi taunted the Congress campaign led by 43-year-old Rahul Gandhi, son of the party president Sonia Gandhi.

"The prime minister himself is not fighting the election. The finance minister is not fighting the election. All its top leaders have run away," Modi said to cheers from a crowd at the polling station in the state's largest city, Ahmedabad.

"After analysing the election process and the voter's mind until now, I can say that this time nothing can save the mother-son government … a strong government will come to power. All citizens have to take part in the festival and make the democracy stronger."

In the seventh phase of the election on Wednesday, nearly 140 million people were eligible to vote for 89 seats in the 543-seat parliament, including all 26 for Gujarat. Elections were also being held in the northern state of Punjab and in the eastern states of Bihar and West Bengal.

Fourteen constituencies in Uttar Pradesh, India's most populous state, were also voting, including Rae Bareli, where the Congress party president Sonia Gandhi is running.

Security was tight in Uttar Pradesh, with tens of thousands of paramilitary troops and police deployed across the state. In elections last week, supporters of political parties took over 11 polling stations in Rampur constituency, said Umesh Sinha, the state's chief electoral officer. A new election was ordered and took place on Tuesday.

Sinha said police were given shoot-on-sight orders to prevent any outbreak of violence or any attempt to disrupt Wednesday's voting.

In Telangana, around 28 million people were expected to vote for 17 seats in parliament and 119 seats in the state assembly.

Telangana, India's 29th state, was carved out of Andhra Pradesh in February after nearly six decades of street protests and strikes.

Telangana supporters say statehood will bring more money to their underdeveloped area. But the move to create Telangana was opposed by the rest of Andhra Pradesh, which will eventually lose its capital city, Hyderabad, to the new state.

Opinion polls have given Modi an edge in the election and indicate that his BJP could form India's next government.

Modi's critics say his image has been tainted by sectarian violence that ripped through Gujarat in 2002, killing nearly 1,000 Muslims. Modi, who has been chief minister of the state since 2001, is widely seen as having done little to stop the carnage.

Modi denies playing a role in the riots, and has never expressed remorse over them. In December, under pressure to speak about the violence, which has become a focal point of his candidacy, Modi spoke of his "anguish" over the bloodshed. The carefully worded statement appeared designed to convey that he had nothing to apologise for.