No one has claimed responsibility for a trio of bomb blasts in India's commercial capital of Mumbai that killed at least 17 people and wounded dozens, as police sifted through clues Thursday to determine who might have carried out the attacks.
Government officials said they have yet to rule out any group or motive. Despite 2008 attacks by gunmen in the city blamed on Pakistan-linked militants, the officials have been careful not to point fingers at Islamabad for Wednesday's bombings.
"The comment I got from some of the experts I spoke to is that this wasn't so well organized," said Mark Magnier, a New Delhi-based correspondent for the Los Angeles Times, who added that the thinking was that "Pakistanis would have organized it better, so this suggests domestic groups."
The Indian Mujahedeen, a homegrown Muslim extremist group, and Maoist rebels known as Naxalites were two possibilities, Magnier told NPR.
The bombings shook three separate neighborhoods within minutes during Wednesday's busy evening rush. The bomb in the Dadar area in central Mumbai was placed on a bus shelter; in the Opera House business district in southern Mumbai, it was hidden under some garbage on the road; in the Jhaveri Bazaar jewelry market a few miles away, it was hidden under an umbrella, near a motorcycle, officials said.
All told, it was the country's worst terrorist strike since the siege of Mumbai that killed 166 people nearly three years ago. After that, India enacted sweeping security reforms and has avoided another major attack in the nearly three years since.
But angry Mumbai residents blamed the government for an apparent intelligence breakdown that they said left the city vulnerable to Wednesday's attacks.
"After the 2008 blast and all the media hype [about safety], we thought we were safe," Anita Ramaswami, a 33-year-old accountant, told The Associated Press. "But things still are the same and people in Mumbai continue to feel vulnerable."
Magnier said there's a "real feeling of anger" and that "there were lots of promises after [the 2008 attacks] that the citizens would be better protected."
Home Minister Palaniappan Chidambaram refused to speculate on who might be behind the attack.
"We are not pointing a finger at this stage," he said, adding, "We have to look at every possible hostile group and find out whether they are behind the blast."
He also defended security measures, saying the latest attack did not represent a failure of the country's anti-terrorism network.
"Whoever has perpetrated this attack has worked in a very, very clandestine manner," Chidambaram said at a news conference after an emergency security meeting.
"We live in the most troubled neighborhood in the world. Pakistan-Afghanistan is the epicenter of terror ... every part of India is vulnerable," he conceded.
Chidambaram lowered the casualty toll to 17 confirmed deaths. He said a severed head was found that could be an 18th casualty. He did not explain the discrepancy from an earlier government statement that listed 21 deaths. Additionally, 131 were injured, 23 of them seriously.
He did not rule out that the blasts might have been aimed at derailing a new round of peace talks between India and Pakistan expected to start in a few days.
News reports said Indian Prime Minister Manmohan Singh was expected to visit Mumbai later Thursday evening.
The Hindu nationalist opposition called Pakistan the hotbed of terrorism in the region, called for its spy agency to be declared a terrorist outfit and criticized the Indian government for not dealing more sternly with Islamabad.
"The government of India must shed its ambivalent attitude to terrorism. The total policy of India toward terrorism should be of zero tolerance," said L.K. Advani, a senior leader of the opposition Bharatiya Janata Party. "Our message to Pakistan should be that you must dismantle the infrastructure for terrorism that you have created."
All three bombs were improvised explosives made of ammonium nitrate with electric detonators, authorities said.
"The IEDs were not crude and showed some amount of sophistication and training," said R.K. Singh, India's home secretary.
Surveillance cameras were in place at all three blast sites, Chidambaram said, but he did not reveal whether any information was gleaned from them.
Elliot Hannon in New Delhi and The Associated Press contributed to this report.