In India's financial capital, Bombay, more than 160 people have been killed and more than 435 others injured as a series of blasts hit commuter trains. Major cities in the country have been put on alert and authorities have appealed for calm.
As many as seven explosions hit packed commuter trains in quick succession at evening rush hour as thousands of commuters were traveling home.
The powerful bombs ripped doors and windows off carriages. Dazed commuters described the terror they faced when the explosions occurred.
Men and women said entire carriages appeared to disintegrate. Some victims recounted how they were helped out by other commuters. Hundreds of people pitched in to ferry the dead and wounded to hospitals.
There was panic in the city of 16 million people as news of the blasts spread. Commuters fled the rail stations as authorities quickly shutdown the extensive train network that links the main commercial district to the citys sprawling suburbs.
Police officials called it a well-coordinated attack. Hours after the explosions, authorities were still struggling to determine the extent of damage.
The explosions in Bombay took place on the same day as Indian Kashmir's summer capital Srinagar was rocked by several grenade blasts that killed eight people and wounded nearly two dozen.
After an emergency meeting following the attacks in the two cities, Prime Minister Manmohan Singh vowed to defeat the evil designs of terrorists. He called for people in Bombay and Srinagar to confront the situation with determination.
Home Minister Shivraj Patil read out a statement from the Prime Minister.
"We will work to defeat the evil designs of terrorists and will not allow them to succeed," he read. "I urge the people to remain calm, not to believe rumors and carry on their activities normally. The government will take all possible measures to maintain law and order and defeat the forces of terrorism."
Bombay has been hit by terror attacks in the past. The worst attack took place in 1993, when serial bomb blasts killed some 250 people.
Security has been stepped up in major Indian cities, including the capital New Delhi.
There has been no claim of responsibility for Tuesdays attacks in Bombay or Srinagar. Suspicion turned on front-line Muslim militant groups fighting to end Indian rule in Kashmir, whom New Delhi has blamed for several terror attacks in the past.
Pakistan's Foreign Ministry issued a statement strongly condemning the attacks in Bombay, and President Pervez Musharraf and Prime Minister Shaukat Aziz offered condolences over the loss of life.