Gunfire and explosions were heard throughout the day Thursday and into the night then the early morning hours from the besieged headquarters of the ultra-orthodox Jewish outreach group Chabad Lubavitch and the Taj Mahal and Oberoi hotels, two of the top gathering spots for the Mumbai elite. Throughout the day, commandoes brought hostages, trapped guests and corpses out of the hotels in small groups while fires erupted periodically and firefighters battled the flames.
State officials said 119 people had died and 288 were injured.
The well-planned attacks began Wednesday night and officials said the gunmen were prepared, even carrying large bags of almonds to keep up their energy during the fight. Their main targets appeared to be Americans, Britons and Jews, though most of the dead seemed to be Indians and foreign tourists caught in the random gunfire.
The gunmen - some of whom strode casually through their targets in khakis and T-shirts - clearly came ready for a siege.
"They have AK-47s and grenades. They have bags full of grenades and have come fully prepared," said Maj. Gen. R.K. Hooda. Vice-Admiral J.S. Bedi, a top naval officer.
Ratan Tata, who runs the company that owns the elegant Taj Mahal, said they appeared to have scouted their targets in advance.
"They seem to know their way around the back office, the kitchen. There has been a considerable amount of detailed planning," he told a news conference.
Throughout the day, black-clad Indian commandos moved through the two hotels room by room in a bid to free the dozens of trapped people.
The Maharashtra state home ministry said dozens of hostages had been freed from the Oberoi and dozens more were still trapped inside. More than 400 people were brought out of the Taj Mahal.
Authorities said they had killed three gunmen at the Taj and were sweeping the Oberoi in search of hostages and trapped people.
It remained unclear just how many people had been taken hostage, how many were hiding inside the hotels and how many dead still lay uncounted.
There were conflicting reports about hostages at the Jewish center. A diplomat closely monitoring the site said people were still being held there, though an Indian state official said earlier eight hostages had been released. Both sources spoke on condition of anonymity because they were not authorized to talk to the media.
Two large blasts were heard at the site early Friday morning.
On Thursday morning, a woman, child and an Indian cook were led out of the building by police, said one witness. The child was identified as Moshe Holtzberg, 2, the son of Rabbi Gavriel Noach Holtzberg, the main representative at Chabad house. The child was unharmed, but his clothes were soaked in blood.
Sandra Samuel, 44, the cook who pulled the boy out the building, said she saw Rabbi Holtzberg, his wife Rivka and two other unidentified guests lying on the floor, apparently "unconscious."
India has been shaken repeatedly by terror attacks blamed on Muslim militants in recent years, but most of those attacks have been coordinated bombings that struck random crowded places: markets, street corners, parks.
These attacks were far more sophisticated - and more brazen.
They began at about 9:20 p.m. with the shooters spraying gunfire across the Chhatrapati Shivaji railroad station, one of the world's busiest terminals. For the next two hours, there was an attack roughly every 15 minutes - the Jewish center, a tourist restaurant, one hotel, then another, and two attacks on hospitals. There were 10 targets in all.
Indian media showed pictures of rubber dinghies found by the city's shoreline, apparently used by the gunmen to reach the area. Both of the luxury hotels targeted overlook the Arabian Sea, which surrounds the peninsula of Mumbai.
At the Chhatrapati Shivaji railroad station, a soaring 19th century architectural monument, gunmen fired bullets through the crowded terminal, leaving the floor spattered with blood and corpses.
"They just fired randomly at people and then ran away. In seconds, people fell to the ground," said Nasim Inam, a witness.
Analysts around the world were debating whether the gunmen could have been tied to - or inspired by - al-Qaida.
"It's clear that it is al-Qaida style," but probably not carried out by the group's militants, said Rohan Gunaratna, of the International Center for Political Violence and Terrorism Research in Singapore and author of "Inside Al-Qaida."
"Yesterday's attack is a watershed because for the first time, the terrorists deliberately attacked international targets," he said, noting that symbolic high-profile targets had been chosen, apparently to magnify the effects of the violence.
Indian media reports said a previously unknown group calling itself the Deccan Mujahideen claimed responsibility in e-mails to several media outlets. The Deccan is a region in southern India that was traditionally ruled by Muslim kings.
Prime Minister Manmohan Singh blamed "external forces" for the violence - a phrase sometimes used to refer to Pakistani militants, whom Indian authorities often blame attacks on.
"The well-planned and well-orchestrated attacks, probably with external linkages, were intended to create a sense of panic, by choosing high profile targets and indiscriminately killing foreigners," he said in address to the nation.
Survivors of the hotel attacks said the gunmen had specifically targeted Britons and Americans.
Alex Chamberlain, a British citizen dining at the Oberoi, told reporters that a gunman ushered 30 to 40 people from the restaurant into a stairway and ordered everyone to put up their hands.
The gunmen "stopped once and asked, 'Where are you from? Any British or American? Show your ID.' My friend said, 'Tell them you're Italian.' And there I was with my hands up basically thinking I was in a lot of trouble."
Chamberlain said he managed to slip away as the patrons were forced to walk upstairs.
One victim was British-Cypriot Andreas Dionysiou Liveras, 73, the owner of a luxury yacht business, said the Cypriot foreign ministry and his brother, Theophanis Liveras.
Andreas Dionysiou Liveras, who was attending a conference, had spoken to the British Broadcasting Corp. from a locked room inside the Taj Hotel before he was killed.
"As we sat at the table we heard the machine gun fire outside in the corridor. We hid under the table and then they switched all the lights off...All we know is the bombs are next door and the hotel is shaking every time a bomb goes off. Everybody is just living on their nerves," he said.
Among the dead were at least four Australians and a Japanese, said the state home ministry. An Italian, a Briton and a German were also killed, according to their foreign ministries.
At least three top Indian police officers - including the chief of the anti-terror squad - were among those killed, said Roy.
Among those foreigners still held captive in all three buildings were Americans, British, Italians, Swedes, Canadians, Yemenis, New Zealanders, Spaniards, Turks, French, a Singaporean and Israelis.
The United States, Pakistan and other countries condemned the attacks.
The motive for the onslaught was not immediately clear, but Mumbai has frequently been targeted in terrorist attacks blamed on Islamic extremists, including a series of bombings in July 2006 that killed 187 people.
Mumbai is one of the most populated cities in the world with some 18 million crammed into shantytowns, high rises and crumbling mansions.
India has been wracked by bomb attacks the past three years, which police blame on Muslim militants intent on destabilizing this largely Hindu country. Nearly 700 people have died.
Since May, a militant group calling itself the Indian Mujahideen has taken credit for a string of blasts that killed more than 130 people. The most recent was in September, when explosions struck a park and crowded shopping areas in the capital, New Delhi, killing 21 people and wounding about 100.
Relations between Hindus, who make up more than 80 percent of India's 1 billion population, and Muslims, who make up about 14 percent, have sporadically erupted into bouts of sectarian violence since British-ruled India was split into independent India and Pakistan in 1947.
Associated Press writers Anita Chang, Erika Kinetz and Jenny Barchfield contributed to this report.