Prerna Suri, Al Jazeera's correspondent in the Indian capital, New Delhi, said "if there is a Pakistani link established to this attack, it will definitely have an impact on these very crucial talks".

'Destabilising talks'

M J Akbar, editor of the Indian Sunday Guardian weekly told Al Jazeera that "the government of India has never in principle objected to talks, but it wants credible proof that the government of Pakistan is actually taking action against the terrorists."

"One obvious pattern is that when hopes over an Indo-Pak dialogue rises or is aroused by the two government, then malevolent factors simultaneously get into play in order to destabilise these talks."

Senior officials from India and Pakistan plan to meet in New Delhi on February 25 to resume talks suspended in the wake of the co-ordinatated attacks in 2008 on India's financial capital, Mumbai, which was blamed on Pakistani-based fighters.

P Chidambaram, the Indian interior minister, admitted on Sunday that the authorities at the moment had no clue about who could have been behind the blast in Pune's famous German Bakery.

"Nothing is ruled out, nothing is ruled in. The investigation is in progress," he said.

"This particular area has been on the radar for quite some time. But this was not an overt attack by a gunman, but an insidious attack with a bomb planted in a soft target.

Foreigners among dead

Saturday's bomb attack was the country's first big assault since the Mumbai attack that left 166 people dead.

Dilip Band, a police official, said "the explosive was in a bag kept in the bakery" and that four foreign women were among the dead but their nationalities were not immediately known.

Chidambaram said police had been alerted to the possibility of attacks on Pune's Osho ashram and Chabad House, a Jewish cultural and religious centre whose members were targeted in the Mumbai attacks, but there had been no intelligence input on the German Bakery.

Al Jazeera's correspondent said the home minister mentioned the possible role of David Headley, arrested in the US last year and charged with scouting targets for the Mumbai rampage, in the attack.

The attack also appeared similar to a wave of bombs that hit Indian cities in the years before the Mumbai attacks, killing more than 100 people.

Police blamed most of those attacks on home-grown Muslim fighters, and a little-known group called the "Indian Mujahideen" claimed responsibility for some attacks. But Hindu hardliners were also accused of masterminding some blasts.