Security has been stepped up across India's commercial capital Bombay (Mumbai) after 11 people were killed in a bomb explosion on a commuter train.
Part of the train's roof was blown off
More than 50 others were injured by the blast, which hit a carriage reserved for women passengers.
It is not yet clear who carried out the attack but police have linked it to a bomb blast in a Bombay suburb three months ago.
This is the fourth bomb blast in Bombay in recent months and comes 10 years after the city was hit by serial bombings.
Railway stations, airports and other vulnerable areas in the city have come under a security blanket and police check-points are in place elsewhere.
"We have started checking bags and frisking commuters at local stations," police official ST Jadhav said.
I saw police helping passengers smeared in blood out of the train
In the Indian capital, Delhi, police have defused six crude bombs at a railway station.
Police officer R S Gumman told the BBC that a person noticed the bombs in a plastic bag near a taxi stand and alerted the police.
He said no timers were attached with the explosives. Delhi is already on high alert following Thursday's blast in Bombay.
Bombay commuters are frightened and are being extra vigilant.
"I am nervous about travelling by train now," says BN Pandey who commutes by train everyday.
"But what can I do? I can't sit at home in fear."
Bomb experts and firefighters are examining the wreckage for traces of the explosive and other forensic evidence.
Police Commissioner RK Sharma told the BBC that initial reports suggested that the explosive used was similar to that used in an attack in December last year.
'Roof blown off'
The explosion happened in the busy Mulund station during the evening rush hour.
One of the passengers on the train was Kirit Somaiya, a politician in the Bharatiya Janata Party of Prime Minister Atal Behari Vajpayee.
History of blasts
Jan 2003 - 30 injured in market blast
Dec 2003 - 23 injured in blast at McDonald's outlet
Dec 2003 - 2 killed in bus blast
Mar 2002 - More than 250 killed in serial blasts
"Part of the roof has been blown off," he told the private Aaj Tak television station soon after the blast.
Another witness, Pratiksha Naik, went to the scene just after the blast.
"I saw police helping passengers smeared in blood out of the train," she said according to the Associated Press.
Hundreds of relatives gathered at hospitals where the injured had been taken.
Laxmikant Patnaik's sister Rena was one of the fatalities.
"My sister was supposed to get married on Sunday, now she is no more. I can't understand why this happened," AP quoted him as saying.
Bombay has been the target of bomb attacks in several instances in the recent past.
In January, about 30 people were injured by a bomb blast in a Bombay market.
A bomb attack on a bus in December left two dead
In December, a bomb on a city bus killed two people and injured about 30 others.
The authorities responded to that attack by ordering the setting up of a force of crack commandos who could respond at short notice to emergencies in the city.
Shortly afterwards, 23 were injured in a blast at a food court housing a McDonald's outlet.
It has never been clear who carried out these attacks.
In 1993, the city was hit by a series of bombs which were blamed on Muslim groups seeking to avenge the destruction of an ancient mosque at Ayodhya.
More than 250 people died in those attacks.