(Changes dateline, adds details)
CHENNAI, India, May 1 (Reuters) - Two bombs went off on a train in the southern Indian city of Chennai on Thursday, killing a woman and wounding nine people, officials said, prompting a security alert in the middle of a mammoth election.
No group has claimed responsibility for the rare attack in the city and police officials said they had no suspects for the moment.
Security is already tight in India as it nears the finish line of the world's biggest election that began early last month and is due to end later in May. Tens of thousands of police have been deployed for the vote.
Explosive devices concealed under seats went off in two coaches shortly after the train stopped at Chennai's central station at about 7 a.m. Two of the nine injured were seriously hurt.
"The incident consists of minor-intensity blasts in two coaches," Rakesh Misra, general manager of Southern Railway, told reporters. "Both are sleeper-class coaches."
No arrests have been made so far, said Anoop Jaiswal, a senior police officer. "We're questioning a lot of passengers," he said.
A team from the National Investigation Agency has joined the investigation in Chennai, an official said.
A security alert was issued in Tamil Nadu state as well as in neighbouring Andhra Pradesh and Madhya Pradesh further afield. Hindu nationalist Narendra Modi, tipped to be India's next prime minister as head of the opposition Bharatiya Janata Party (BJP), was due to campaign in Andhra Pradesh on Thursday.
Even before the explosions, security agencies had increased surveillance on suspected members of the Islamist Indian Mujahideen group, which has carried out a wave of low-level attacks in towns across India in recent years.
Police believe the IM was behind blasts at a campaign rally that Modi addressed in eastern India last October. The IM, which says it wants to establish a caliphate, poses the most serious threat so far from a home-grown group in Hindu-majority India. (Reporting by Sriram Srinivasan in CHENNAI; Writing by Sruthi Gottipati and Sanjeev Miglani; Additional reporting by Aditya Kalra; Editing by Ron Popeski)
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