The bombs used in last Friday's Bengaluru blasts revealed a greater degree of sophistication than the bombs used in Ahmedabad on Saturday, a highly-placed government source told reporters aboard AI 001 carrying Prime Minister Dr Manmohan Singh [Images] to the South Asian Association for Regional Cooperation summit in Colombo.

There were similarities in the bombs used in the Jaipur and Ahmedabad [Images] blasts, the source added.

Dismissing the theory that the blast had targetted Bharatiya Janata Party-ruled states, the source, who spoke on condition of not being identified, felt availability, opportunity and the movement of personnel had determined the choice of cities for last week's blasts.

Bengaluru [Images], Hyderabad, Ahmedabad and Mumbai, the source added, had all come under the terrorists' radar.

The government agencies are still trying to identify the antecedents of Indian Mujahideen, the source revealed, adding that it was still too early to determine if Pakistan's Inter Services Intelligence was behind the blasts.

There was no such ambiguity over the ISI's involvement in the July 7 bombing of the Indian embassy in Kabul. However, the source felt, "We must make a distinction between the Government of Pakistan and rogue elements in the intelligence establishment."

"Like President Bush, we too would like to know who is in charge of the ISI," the source said.

Pakistan's ISI: Rogue, responsible, or both?

It is unclear if Dr Singh will specifically raise the Kabul bombing or the recent firing across the Line of Control at his meeting with Pakistan Prime Minister Yousuf Raza Gilani on Sat evening.

It will be the declared Aishwarya Rai's [Images] fan's first encounter with the Indian leader.

The security agencies, the source added, are dealing with terrorists with sophisticated understanding of technology as evident by the hacking of the American Kenneth Haywood's wi-fi internet account in Navi Mumbai and the use of circuit boards in the unexploded Surat bombs.

While it was too early to link foreign agencies with last week's blasts, the source felt that there was a clear local hand in the conspiracy.

While the government hopes that Friday's meeting at the International Atomic Energy Agency will go well -- "though different countries have non-proliferation concerns" -- the source said, revealing that Dr Singh's team is working hard to ensure "a clean waiver" at the Nuclear Suppliers Group. Translated, it means that India would like a comprehensive agreement with all nations rather than one where each NSG member imposes individual conditions on the country.

Though no date has been fixed for the NSG meeting, the prime minister's emissaries have logged many thousands of miles trying to win support for India at the NSG where consensus is essential. National Security Advisor M K Narayanan has already travelled to Canada [Images] and Britain (he is scheduled to visit Russia [Images] and France [Images] shortly), while Prithviraj Chavan, minister of state in the Prime Minister's Office, has met Chinese Vice Minister for Foreign Affairs Dai Bingguo in Beijing [Images] with apparently positive results.

Unprecedented security surrounds this, the first visit by an Indian prime minister to Sri Lanka [Images] in 10 years � then prime minister A B Vajpayee visited the island nation also for the SAARC summit. An Indian Air Force helicopter will fly the prime minister to his hotel from the Bandaranaike International Airport, Indian Coast Guard ships have increased their patrolling of the Lankan coast, Indian troops are assisting the Sri Lanka army in manning air defence equipment while Indian special soldiers have already arrived in Colombo for Dr Singh's visit.