At least 70 people have been killed by seven bombs in what police described as a well-coordinated attack on rush-hour commuter trains in the Indian financial capital of Mumbai.
The Associated Press put the death toll at up to 100. Officials said more than 300 people were injured in the blasts, which took place between 6:20 and 7 p.m. (1250 and 1330 GMT) when the trains were packed with commuters making their way home.
A senior Bombay police official, P.S. Pasricha, told The Associated Press the explosions were part of a well-coordinated attack.
Vilasrao Deshmukh, the chief minister of Maharashtra state, where Bombay is located, said bombs caused all seven blasts, AP added.
Indian Home Minister Shivraj Patil said authorities had had some information an attack was coming, "but place and time was not known."
A correspondent for CNN's sister network, CNN-IBN, reported seeing 15 bodies at the Matunga train station in Mumbai, formerly known as Bombay.
Commuters fled rail stations in panic after the explosions and cellphone lines were jammed, Reuters reported. Video from one station showed people with blood on them being treated, other commuters carrying victims and some people lying motionless near train tracks.
At least one train was split in half by the explosion.
The Western Railway system -- used by 4.5 million people daily -- was shut down and Mumbai's subway system was put on high alert after the blasts in the city's western suburbs. Police in the capital of New Delhi also heightened security.
Airports across India were also put on high alert, and Prime Minister Manmohan Singh called an emergency meeting of his ministers after the explosions.
One person was arrested in New Delhi in police raids after the explosions, CNN-IBN reported, but there was no claim of responsibility for the attacks. The blasts took place in quick succession -- a tactic used by Kashmiri militants who have often targeted Indian cities.
Earlier Tuesday, a grenade attack in Indian-controlled Kashmir killed at least four people. Authorities believe militants are responsible for that attack on a minibus in Srinagar. There was no immediate indication of a connection to the Mumbai blasts.
The blasts hit trains or platforms at the Khar, Mahim, Matunga, Jogeshwari, Borivili and Bhayander stations, in that order. Another hit a train between the Khar and Santa Cruz stations, a police official told CNN-IBN.
One CNN-IBN correspondent who was on a train hit by an explosion said the train was just leaving the station when the blast occurred. Several people jumped from the train and were killed when they were hit by the train.
"Limbs (are) lying everywhere, bodies (were) cleared from the tracks by local business owners who rushed from their shops," the correspondent said.
On March 7, 14 people were killed in attacks on a temple and a rail station in Varansi. On March 12, 1993, more than 250 people were killed in Mumbai when 13 bombs exploded in several locations in the city.
The city's commuter rail network is among the most crowded in the world.
Kashmir was divided between India and Pakistan in war after independence from Britain in 1947, and they fought another war over the region in 1965.
Militant groups have been fighting Indian rule in Kashmir, demanding the mostly Muslim region's independence, or its merger with Pakistan.