The bombs used in the triple terror attacks in Mumbai, killing 17 people, had some degree of sophistication, officials say.
They were not remote-triggered, Indian authorities have said.
India is yet to determine which terror group is responsible for the attacks on Wednesday, the latest in a string upon the financial center of the country since the 1990s.
Ammonium nitrate was used in the blasts and the attacks were well co-ordinated, The Times of India reports.
The bombs used for the blasts were not crude and showed some degree of sophistication, union home secretary RK Singh told local media, it reports.
He said the bomb at the Opera House was hidden under garbage while at Dadar, it was placed over a bus shelter.
At the famous jeweler bazaar, Zaveri Bazar, the bomb was concealed under an umbrella near a motorcycle, he said.
Union home minister P Chidambaram said 17 people have been confirmed dead, after revising the toll downwards from an original estimate of 21.
However, the toll could go up to 18 as one body with a severed head had to be identified. So far, 131 people have been injured in the terror attack, of whom 26 are seriously injured, the Times of India reports.
Twenty-six injured have been discharged and another 82 are stable, he added.
Intelligence agencies received no warnings before the blasts, the biggest attack since Pakistani-based militants rampaged through the financial hub in 2008, Chidambaram said on Thursday, Hindustan Times reports.
"There was no intelligence regarding a militant attack in Mumbai," Chidambaram told a news conference in Mumbai.
"(Maybe those) who perpetrated the attacks worked in a very clandestine manner, maybe a very small group that has not communicated with each other."
The triple blasts have received extensive media in India.
The Times of India says the city has become a 'Hot hunting ground for terror'.
"Repeatedly hit over a half-a-dozen times since the early 1990s, India's financial capital has now become the favorite hunting ground for terror outfits," the paper says.
Over 600 people have died in these attacks, it reports.
"The macabre dance of death has unnerved citizens amid fears that Mumbai may go the Karachi way. Pakistan's port city, barely 800km from Mumbai, has been wracked with violence and bloodbath over the past few years," the report says.
In a report, The Hindustan Times newspaper asks 'Why is Mumbai targeted again and again'?
The report quotes Maharashtra state minister Chhagan Bhujbal as saying: "Mumbai and Delhi will always remain terror targets... "An attack on a city like Mumbai always rocks the nation and gets the attention of the world, which is what terrorist groups want."