Indian police and emergency services have been working into the night to cope with the aftermath of eight purported bomb attacks on commuter trains in Mumbai earlier in the evening.
More than 160 people were killed and more than 460 injured in what officials said was a well-coordinated bomb attack by terrorists.
India's major cities were put on high alert after the blasts, which appeared timed to impose maximum carnage in the bustling city of 16 million.
There was no immediate claim of responsibility for the attacks, but the blasts came in quick succession - a common tactic employed by Kashmiri militants that have repeatedly targeted India's cities.
The militants are fighting New Delhi's rule in disputed Kashmir.
Speaking earlier on RTÉ Radio's 5-7 Live, the Indian correspondent, Rahul Bedi, said criminal gangs might also have been behind the attacks.
The country's Prime Minister, Manmohan Singh, has appealed for calm.
Ahern joins international condemnation
The Irish Government has joined international condemnation of the attacks.
The Minister for Foreign Affairs, Dermot Ahern, said the attacks were clearly designed to spread maximum terror among people going about their daily lives.
Extending sympathy, he said no cause or grievance could justify attacks such as these on innocent civilians.
The city's police chief earlier said the explosions were obviously the work of terrorists.
Train carriages on the tightly-packed trains were blown apart. Television images showed footage of dead bodies in the wreckage, as well as many dazed commuters covered in blood.
The blasts come just hours after suspected Islamist militants killed seven people, six of them tourists, in a series of grenade attacks in Indian Kashmir's main city, Srinagar.
At least 27 people were also injured.
In the bloodiest attack, a grenade thrown inside a tourist bus killed five people and wounded 12 others.
Another blast outside a tourist reception centre wounded six people.
