Witnesses at many of the locations reported that the gunmen, armed with AK-47 rifles and grenades, were between the ages of 20 and 25 years and were speaking in Hindi or Urdu.
Security camera footage of the militants show fresh-faced youths seemingly enjoying the mayhem they had unleashed.
At least 10 different locations were hit in the series of coordinated attacks, and while the vast majority of the dead were Indians, some reports said the assailants tried to single out Westerners, particularly Americans and Britons.
At the Trident-Oberoi, survivor Rakesh Patel told NDTV, "They wanted anyone with British or American passports. Say anyone who had an American or British passports, they wanted to know, so I guess they were after foreigners."
The reason for the attack was unclear. One of the militants called an Indian TV station from the Trident-Oberoi to demand that mujahideen prisoners be released.
"We want all mujahideens held in India released and only after that we will release the people," he said.
"Muslims in India should not be persecuted. We love this as our country but when our mothers and sisters were being killed, where was everybody?" he told the channel.
ABC News' Nick Watt, the Associated Press and Reuters contributed to this report.