New Delhi ? At least seven powerful bombs detonated in commuter trains and stations during the Tuesday evening rush hour in Bombay, India’s commercial capital, killing at least 147 people and wounding close to 439. Authorities called the explosions a coordinated terror attack.

In monsoon rain, rescue workers helped dazed and bleeding survivors from rail cars mangled by the quick succession of blasts, television images showed. Train doors were blown off, and luggage and other debris littered the platforms.

There was no immediate assertion of responsibility for the attacks, which appeared to focus on first-class train cars. Authorities have blamed previous terrorist strikes in Bombay on indigenous Muslim groups motivated by sectarian hatred.

“This is a painful incident. I see this as a part of a larger conspiracy,” Vilasrao Deshmukh, the chief minister of Maharashtra state, said on New Delhi Television channel. “The blasts occurred between 6 and 6:30 p.m. when the local trains are running at their busiest.” Bombay, also called Mumbai, is the capital of Maharashtra.

The city’s commuter rail system is one of the most heavily patronized in the world, carrying about 6 million people a day. The explosions, all along a single rail corridor in a western sector of the port city, caught passengers in very close quarters.

The blasts came hours after a series of grenade attacks killed five Indian tourists and injured more than 30 other people in Srinagar, summer capital of the Indian-controlled portion of Kashmir. Muslim insurgents have been fighting Indian authority there, seeking union with Pakistan, a Muslim-majority country.

Police investigate a train coach destroyed by a bomb blast Tuesday at Matunga railway station in Bombay, India. Eight explosions ripped through packed commuter trains during rush hour, killing nearly 150 people and injuring another 439 in what officials said was a well-coordinated bomb attack by terrorists.

India’s rail systems and airports were put on high alert after the explosions in Bombay. Phone lines to Bombay from New Delhi, the Indian capital, were jammed.

Prime Minister Manmohan Singh called an emergency meeting Tuesday with his national security advisers to discuss the attacks.

“The series of blasts in Mumbai and in Kashmir are a shocking and cowardly attempt to spread fear and terror among all citizens. I condemn these shameful acts, and I reiterate our commitment to fighting terror in all its forms,” the prime minister said in a statement read by Home Minister Shivraj Patil.

Patil said that any possible links between the two attacks would be investigated.

Bombay has seen such terror attacks in the past as well. In 1993, more than a dozen bombs exploded in Bombay, killing 257 people and injuring hundreds. In March 2003, a bomb killed 10 people on a passenger train. In August of that year, two taxis packed with explosives blew up near a busy city market, killing 52 and wounding more than 100.

Those attacks were blamed on indigenous Islamic terrorists and followed large-scale sectarian violence between the Hindu and Muslim communities.