A previously unknown group calling itself Deccan Mujahedin said it carried out the attack, though experts warned that the claim might be false. Mumbai and other Indian cities have suffered a spate of terrorist attacks in recent years, most of which the Indian government has blamed on Muslim extremists.
Previous terrorist attacks have mostly involved bombs left in public spaces such as markets and parks, causing indiscriminate casualties.
In sharp contrast, Wednesday's attacks were a brazen, frontal assault using automatic weapons.
The targets included police headquarters in south Mumbai, where some officers were pinned down by gunfire.
The victims included Mumbai's anti-terrorism chief, Hemant Karkare, and two of his senior police officers, which complicated the law enforcement response to the attacks. Television video showed Karkare donning a flak jacket and helmet minutes before heading into one of the hotels.
Witnesses said the attackers appeared to fire at random and made no effort to hide their identities, which, experts suggested, signaled a readiness to die. Police released a picture of a man with a serene smile wearing a blue T-shirt and holding an automatic weapon, whom they identified as one of the train station attackers.
Local government officials said as many as four attackers were killed and nine suspects were arrested.
Terrorism experts said the late-evening timing offered several potential advantages for the attackers. Security is generally more lax as businesses prepare to close.
Also, there's less traffic in the congested city at that time, making it easier to position a large number of attackers at various sites. And it allows the story to hit news cycles in Europe and North America, with global publicity a key objective among terrorists hoping to undermine stability and spread fear.
Near the Vile Parle station of the city's Western train line, a bomb exploded in a taxi on the highway about 10 p.m. An hour later, parts of the vehicle could be seen scattered up to 100 feet away. Four injured people nearby were taken to a hospital.
Within minutes, police officers were cordoning off all major roads, stopping even emergency vehicles as reports came in that two attackers had hijacked a police van.
Friends and guests told reporters that they received frantic calls from loved ones hiding under beds and tables in darkened hotel rooms.
