MUMBAI - The death toll from a series of bombs which exploded on packed commuter trains and stations in India's financial hub Mumbai overnight has risen to 174, CNN reported this morning.

There was no immediate claim of responsibility for the seven bomb explosions that took place within about 10 minutes during evening rush hour wounding hundreds.

But suspicion was likely to centre on Muslim militants fighting New Delhi's rule in disputed Kashmir, who have been blamed for several bomb attacks in India in the past.

Foreign Affairs Minister Winston Peters said it was too early to say if any New Zealanders had been caught in the blasts. Officials were continuing to work closely with Indian officials to clarify the situation.

The first attack took place at 6.24pm last night (12.54am NZT today) with the others following in quick succession.

Commuters fled suburban rail stations in Mumbai (formerly Bombay) in panic after the explosions and mobile phone lines were jammed. Hundreds of dazed passengers walked along the railway tracks.

Television showed twisted rail carriages and people in torn, blood-stained clothes carrying the dead and wounded on stretchers as steady monsoon rain fell. A policeman was shown carrying two white, blood-stained bundles of what appeared to be body parts.

"The blasts happened when the trains were most crowded," D.K Shankaran, chief secretary of the state of Maharashtra, of which Mumbai is the capital, told Reuters.

At peak hours, each nine-car passenger train in Mumbai carries over 4,500 people, about three times the rated capacity.

Prime Minister Manmohan Singh called for calm and Sonia Gandhi, leader of the ruling Congress party, expressed her grief.

"I urge the people to remain calm, not to believe rumours and carry on their activity normally," Singh said in a statement, calling the explosions a "shameful act".

The United States called the bomb attacks "senseless acts of violence". Pakistan, the EU, France and Britain also condemned the explosions.

At the city's Sion hospital, relatives were frantically looking for friends and relatives. Scores pored over a board displaying a list of injured.

"I spoke to him 10 minutes before he died," said Haji Mastan, sobbing uncontrollably after being told about the death of his cousin Mukti Darvesh, who was travelling on one of the trains.

"Why did it have to end like this? He was young and he has children." Some of the people who entered a makeshift morgue were unable to identify badly mutilated bodies.