The Indian government said on Sunday it had little idea who was behind a bomb in a tourist eatery in Pune that killed nine people, an attack that some experts said could be the work of home-grown militants.

The bomb that also wounded 57 in Pune was the country's first big attack since the 2008 Mumbai massacre and appeared to target Indian and foreign tourists. At least one foreigner whose identity had not yet been established was killed.

German Bakery, located close to a Jewish centre and a religious retreat frequented by foreigners, was a soft target in an area that had been on the radar of intelligence officials, Home Minister Palaniappan Chidambaram said.

"Nothing is ruled out, nothing is ruled in. The investigation is in progress," Chidambaram told reporters.

"There is no intelligence failure. 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."

Authorities put airports and railway stations on high alert after the blast and extra security was given to South African and Indian cricket teams playing in the country.

The explosion came a day after India and Pakistan agreed to high-level talks in New Delhi on Feb. 25, suspended after Pakistani militants killed 166 people during a three-day rampage through the financial capital of Mumbai in November 2008.

Any sign of Pakistani involvement in the Pune attack would worsen relations between the two nuclear rivals and further destabilise a region overshadowed by war in Afghanistan.

Pune police had been alerted to the possibility of attacks on Osho ashram and Chabad House, which had also been targeted during the Mumbai attacks, Chidambaram said. But there had been no intelligence input on German Bakery, he said.

Chidambaram said the Pune ashram was one site surveyed by David Headley, arrested in the United States last year and charged with scouting targets for the Mumbai rampage.

The government suspects he has links to Pakistan-based militant group Lashkar-e-Taiba that is blamed for the Mumbai attacks.

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

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

"The bomb appears to have been not a sophisticated one that could have required any special training," said B. Raman, director of the Chennai-based Institute For Topical Studies.

"The expertise involved could have been locally acquired. One must control the reflex to point an accusing finger at Pakistan."

Among the injured were Iranians, Sudanese, a Taiwanese and a German.

"I don't think any particular nationality was targeted. They targeted a place where young people, both foreigners and Indians, congregated," Chidambaram said.

In response to a question on whether the proposed talks between India and Pakistan would now be suspended, Chidambaram said that was a diplomatic process that would be determined in Delhi after he returned there.

Authorities have warned of renewed threats of attacks on Indian soil and stepped up security in recent months.-Reuters