In India's financial capital, Bombay, at least 90 people have been killed and hundreds injured by seven blasts that hit commuter trains.
Powerful explosions rocked Bombay's suburban rail network during evening rush hour, ripping doors and windows off packed train carriages and killing and wounding scores of passengers.
Television footage showed pictures of dazed and injured people being carried by fellow travelers. Hundreds of commuters fled in panic.
After an emergency Cabinet meeting, Indian Home Minister Shivraj Patil expressed the governments resolve to fight terror.
"We will work to defeat the evil designs of terrorists and will not allow them to succeed. I urge the people to remain calm."
Bombay has been hit by terror attacks in the past. The worst attack took place in 1993, when several bomb blasts killed about 250 people.
The blasts in Bombay took place on the same day as Indian Kashmir's summer capital was rocked by a series of grenade blasts.