Three explosions rocked Mumbai in quick succession Wednesday evening, killing at least 21 people and leaving nearly 150 injured in -- making it the deadliest terrorist attacks on Indian soil since 2008.
The first blast erupted in the Jhaveri Bazaar at 6.54 p.m. local time, the second struck a minute later in a business district known as Opera House and the third hit the neighbourhood of Dadar within 10 minutes.
Home Minister Palaniappan Chidambaram said the timing of the blasts suggests "this was a co-ordinated attack by terrorists." He added that Mumbai has been placed on high alert.
Reports from the scene described blood-covered bodies lying in the streets while survivors hugged and wept, while police questioned witnesses.
Police were scrambling to determine the cause and find those responsible, with bomb squad investigators searching vehicles for explosives amid charred remains of motorcycles, shattered storefronts and a demolished bus stop.
One eyewitness at Jhaveri Bazaar described two motorcycles exploding in flames and saw at least six bodies.
"People were shouting 'Help me, help me,"' the man told Headlines Today television.
Prime Minister Manmohan Singh condemned the bombings and pleaded with residents of the country's financial capital "to remain calm and show a united face."
At least 141 people were injured in the attacks, which were the first on Mumbai since November 2008 when armed militants went on a rampage that left 166 dead. In that three-day siege, 10 armed men targeted two luxury hotels, a Jewish centre and a railway station.
Bhupinder Chaubay, a reporter in New Delhi with CNN's IBN Network, said the death toll in Wednesday's attack could have been much higher since the explosions occurred in high-density areas as office workers and commuters were heading home.
"The only silver lining in this entire episode...is the fact this was some kind of a low intensity blast," he said.
Indian officials declined to speculate on who could be responsible for the attacks, and no one claimed responsibility immediately after the explosions.
Past attacks have been blamed on militants based in Pakistan. Indian officials have also charged that Pakistan's powerful spy agency helped carry out and fund previous attacks.
Part of the difficulty with determining who carried out the attacks is that there are "a plethora of terrorist groups in India," said security expert Alan Bell.
Whoever is responsible for the bombings likely learned from the 2008 Mumbai attacks, Bell told Â鶹´«Ã½ Channel, but it appears they had limited resources to work with.
"This is probably another group within in India that's trying to make a name for themselves," he said.
It's unclear whether the bombings may have been orchestrated to disrupt peace talks between India and Pakistan, which were suspended after the 2008 Mumbai attacks and only resumed a few months ago.
International reaction
Hours after Wednesday's attacks the Pakistani government decried the loss of life and injuries they inflicted.
In Washington, U.S. President Barack Obama condemned the bombings, saying in a statement that his country "will stand with the Indian people in times of trial, and we will offer support to India's efforts to bring the perpetrators of these terrible crimes to justice.
"I have no doubt that the India will overcome these deplorable terrorist attacks."
Meanwhile, U.S. Secretary of State Hillary Clinton said she plans to visit the South Asian country as scheduled next week. Speaking to reporters in Washington, she said "it is more important than ever that we stand with India."
Federal Immigration Minister Jason Kenney also denounced the attacks, adding that he doesn't know of any Canadian citizens who were injured or killed.
With files from The Associated Press
