NEW DELHI — Indian authorities on Saturday issued a national alert after 9 people were killed and at least 57 were wounded when a bomb exploded at a bakery in a neighborhood popular with foreign tourists in the western Indian city of Pune.

Investigative teams from New Delhi were flying to Pune, and the authorities had not linked the probable attack to any terrorist organizations or publicly identified any suspects or motive. But the timing is certain to complicate the recent overture by India to resume the high-level talks with Pakistan that broke off after the November 2008 attacks on Mumbai by Pakistani militants. India has demanded that Pakistan confront domestic terrorist groups as a condition of resuming diplomatic talks.

The Indian home secretary, G. K. Pillai, speaking to reporters on Saturday night, said the explosion occurred in a Pune neighborhood visited by David Headley, the son of a former Pakistani diplomat who has been charged with helping to plot the Mumbai attacks. Mr. Headley is accused of doing reconnaissance for the attacks for a Pakistan-based terrorist group called Lashkar-e-Taiba.

Mr. Pillai said the police had been alerted last October that Mr. Headley “had surveyed 200 yards from the bakery,” but he added that it was too early to say if Lashkar-e-Taiba was involved in the Pune blast.

At a news briefing on Sunday morning in Pune, the country’s home minister, Palaniappan Chidambaram, said that the area had been identified to be a potential “soft target” for terror attacks, and that businesses in the area had been “sensitized” to this fact.

He said that it appeared that someone had left a backpack beneath a table inside the eating area of the bakery and apparently left. When the bomb exploded, a group of four or five women and at least one man were sitting at that table, he said.

“That area is on the radar of terrorists,” Mr. Chidambaram said. In particular, he said that there was concern about the nearby Chabad House, which attracts Israeli visitors.

Mr. Chidambaram said there was “no intelligence failure” in the episode.

“Everybody was aware that the area was a vulnerable area,” he said, adding that it was frequented by young people, Indians and foreigners, and that many of the injured were between the ages of 22 and 35.

The explosion happened on Saturday evening as the streets were crowded with people.

Wounded survivors were rushed to local hospitals, with several people reported in critical condition. Mr. Pillai confirmed that at least one of the dead was a foreigner, of unconfirmed nationality. The eatery, called German Bakery, is near the Osho Ashram, a high-end yoga and meditation retreat that caters to visitors from around the world.

In the 2008 Mumbai attacks, a Chabad House, part of a worldwide network of Jewish outreach centers, was among the sites singled out, along with hotels, a restaurant and a train station. The attack left 163 people and 9 gunmen dead.

In Pune, the police had started their investigation as teams from the Central Bureau of Investigation and the National Investigative Agency were en route from New Delhi. Ashok Chavan, chief minister of the state of Maharashtra, which includes Pune, said investigators initially thought the blast had been caused by a gas explosion.

In his interview, Mr. Pillai, the home secretary, noted that central intelligence agencies had notified the authorities in Maharashtra last year that Pune could be a terrorist target, based on the investigation of Mr. Headley. Pune is less than 100 miles from Mumbai, which has seen a huge police mobilization in recent days after a right-wing political group threatened to disrupt the opening of a movie.

Meanwhile in New Delhi, the Home Ministry issued a national alert warning people to notify the police if they saw any unidentified bags or packages. Across the city, the opposition Bharatiya Janata Party was already questioning whether the apparent attack was the result of complacency regarding security measures by the national government, led by the Congress Party. A spokesman also added: “It seems that terror has struck back again in the backdrop of talks with Pakistan.”