NEW DELHI: Indian authorities are stepping up security for political leaders, fearing possible militant attacks as a general election approaches, Home Ministry officials and police said yesterday.

Intelligence agencies have warned that ruling Congress party chief Sonia Gandhi, her son Rahul Gandhi and the Hindu-nationalist Bharatiya Janata Party leader L.K. Advani, could be targets, they said.

The country remains tense after militants killed nearly 200 people in a strike on the financial hub of Mumbai last November.

“The home minister has warned all political parties to be on the alert during their campaigns,” Onkar Kedia, a Home Ministry official, told Reuters.

More than two million security personnel will be deployed in the world's largest democratic exercise from April 16 to May 13, for which 714 million people are eligible to vote.

Authorities said they were securing all buildings near rally sites and will have commandoes and sniffer dogs when high-profile leaders address large gatherings.

The main battle will be between the Congress Party-led coalition, known as the United Progressive Alliance (UPA), and the National Democratic Alliance (NDA), led by the Hindu-nationalist Bharatiya Janata Party (BJP).

“Security will be very, very tight as we approach elections. We are wary of possible strikes,” Rajan Bhagat, a Delhi Police official said yesterday. “We are working on that now.” Some 400 people have been killed in about a dozen militant strikes over the last year.

Mewnwhile, the leader of the country’s biggest communist party said he would be open to talking to the ruling Congress party to support the formation of an alternative “Third Front” government after the elections.

The statement by Prakash Karat, head of the Communist Party of India (Marxist), signals a shift in India's political sands, opening up the chance of a Left-Congress pact after they split angrily last year over a civilian nuclear deal with the United States.

The CPI(M) and smaller left parties were crucial in giving the ruling Congress party-led coalition a majority in Parliament from 2004 to 2008, but they blocked many economic reforms such as privatization.

“We can do business with them and ask them to support an alternative secular formation, it's possible — why not, I don't rule it out,” Karat said in an interview with NDTV news channel.

The CPI(M) is a major force behind a “Third Front” of smaller regional parties that aims to challenge Congress and the BJP.

“It's a big change, especially from someone as hawkish as Karat,” said political analyst Amulya Ganguli.