MUMBAI - The number of people killed in the bombings on packed commuter trains and rail stations in India's financial capital rose to 179 after more victims died of their wounds at hospitals, police said today.

"The toll could go up because many of the 661 injured are critical," Shivaji Mohit, a duty officer at Mumbai Police control room, said.

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Police stepped up security across India earlier today as India's Prime Minister Manmohan Singh appealed for calm.

"I urge people to remain calm, not to believe rumours and carry on their activity normally," Prime Minister Singh said, calling the seven explosions that took place during the evening rush hour local time (around 1am today NZT) a "shameful act".

There was no immediate claim of responsibility for the attacks 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.

Extra security was brought in countrywide both to prevent any further attacks and to guard against any possible backlash against the minority Muslim community.

The blasts brought worldwide expressions of outrage.

"We condemn thoroughly this terrible terrorist incident," US Secretary of State Condoleezza Rice told reporters in Washington. "We will stand with India in the war on terror."

Police inspector Ashok Jadhav had earlier told Reuters the bomb blasts had killed 163 people and wounded around 460. Police this afternoon said the death toll has risen to 179, with the fear it could rise even higher with many of the 661 injured being critical.

In the aftermath, hundreds of dazed passengers walked along railway lines and many helped pull bodies from mangled carriages and rush the injured to hospitals as monsoon rain fell.

"I took out at least 35 dead bodies from the trains," a middle-aged man told local TV, weeping uncontrollably. "There were people without hands and limbs and we took them to hospital."

A policeman was shown carrying two white, blood-stained bundles of what appeared to be body parts.

"Such acts cannot possibly be excused by any grievance," UN spokeswoman Marie Okabe said in New York.

Commuters fled suburban rail stations in panic after the explosions and mobile phone lines were jammed. TV stations said an eighth bomb was defused in a Mumbai suburban station.

D.K Shankaran, chief secretary of the state of Maharashtra, of which Mumbai is the capital, said the city would bounce back.

"Mumbai will be up tomorrow. Every single school, college and office will remain open," he told Reuters.

But India's financial markets were expected to suffer, with analysts saying the attacks were likely knock foreign investor confidence.

Sonia Gandhi, leader of the ruling Congress party, expressed her grief before heading for Mumbai.

At the city's Sion hospital, relatives frantically searched for friends and relatives, poring over lists of the injured.

The blasts occurred on five trains and at two stations in Mumbai's western suburbs, which are linked to the downtown office and business areas mainly by an overground rail network used by some 6.5 million people each day.

All suburban train services in the city were suspended after the blasts but by this afternoon a limited service was running on the western line, along which the attacks took place.

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

The Mumbai blasts came hours after suspected Islamist militants killed seven people, six of them tourists, in grenade attacks in Indian Kashmir's main city, Srinagar, police said, the most concerted targeting of civilians in months.

Kashmir has been split between India and Pakistan since shortly after the two countries gained independence from Britain in 1947, but both claim it in full.

Pakistan's Foreign Ministry said the leadership strongly condemned the "terrorist attack" in Mumbai.

A metropolis of about 17 million people formerly known as Bombay, the city has been hit by bomb blasts in the past decade.

More than 250 people died in a string of bomb explosions there in 1993 for which authorities blamed underworld criminal gangs. Those attacks followed the demolition of a mosque in the Hindu holy city of Ayodhya.