A little-known group that police say has ties to Kashmir's (search) most feared militants claimed responsibility Sunday for a series of terrorist bombings that killed 59 people in New Delhi (search).

Authorities said they already had gathered useful clues about the near-simultaneous blasts Saturday night that ripped through a bus and two markets crowded ahead of the Hindu festival of Diwali, one of the year's busiest shopping seasons.

Investigators reportedly raided dozens of small hotels across India's capital looking for possible suspects, and police said "numerous" people were being questioned.

The attacks came at particularly sensitive time as India and Pakistan (search) were hashing out an unprecedented agreement to partially open the heavily militarized frontier that divides the disputed territory of Kashmir to speed relief to victims of a massive earthquake earlier this month.

The agreement was finalized early Sunday, and Indian officials appeared hesitant to quickly put the blame for the bombings on Pakistan-based militants, unlike in previous terror attacks during a 16-year-old insurgency by Islamic separatists in India's part of Kashmir.

India's accusations of Pakistani involvement in a 2001 attack on parliament put the two nuclear-armed rivals on the brink of a fourth war. But they pulled back and, after pursuing peace efforts since early last year, both appeared intent on keeping the atmosphere calm.

"We have lots of information but it is not proper to disclose it yet," Indian Home Minister Shivraj Patil told clamoring journalists after an emergency meeting of the Cabinet called to discuss the attacks. "Our people are making good progress. The investigation is going well."

A man called a local news agency in Indian Kashmir to say the militant Islamic Inquilab Mahaz (search), or Front for Islamic Uprising, staged the bombings, which police said killed 59 people and wounded 210.

The caller, who identified himself as Ahmed Yaar Ghaznavi, said the bombings were "meant as a rebuff to the claims of Indian security groups" that militants had been wiped out by security crackdowns and the Oct. 8 earthquake that devastated the insurgents' heartland in the mountains of Kashmir.

A senior police officer in India's Jammu-Kashmir state said the caller's name was not familiar to intelligence agencies, and New Delhi's deputy police chief, Karnail Singh, said the group had not been very active since 1996.

However, while Singh refused to comment on the claim of responsibility, he said the group is linked to the Pakistan-based Lashkar-e-Tayyaba (search), the most feared of the dozens of Kashmiri militant groups.

A leading anti-terrorism expert said earlier that the timing and nature of the blasts appeared to indicate the work of Lashkar.

"It looks like Lashkar. They are the most active group here," said Vikram Sood, the former head of the Research and Analysis Wing, India's foreign intelligence agency.

Lashkar and some other Kashmiri groups are known to have expertise in using the powerful explosive RDX, and a police officer with knowledge of the investigation said forensic experts were studying whether RDX was used in the attack.

He said witnesses reported that the biggest explosion created a huge ball of fire like that usually caused by RDX. The officer agreed to discuss the probe only if granted anonymity because he was not authorized to speak with journalists.

Police said they also were looking for a man in his 20s who refused to buy a ticket on a bus and got off in the Govindpuri neighborhood, leaving behind a large black bag. When some of the 40 passengers raised an alarm, the driver and conductor examined it and threw it out just as the blast occurred, injuring them both along with seven others.

Several Indian television stations said dozens of hotels in New Delhi had been raided after the bombings and suspects were detained.

Singh, the deputy police chief, refused to comment on the reported raids. He insisted that "no one is under detention," but said many people were being questioned.

After the attacks, the Hindu nationalist Bharatiya Janata Party (search) — India's main opposition party — called on the government to review what it called the "soft border" policy agreed to with Pakistan.

The deal reached early Sunday will allow people to cross the frontier in Kashmir at five points starting Nov. 7 to help get food, shelter and medical aid to victims of the quake, which killed about 80,000 people and left 3 million homeless, most in Pakistan.

Opening the border is a touchy issue in India because of the uprising by Islamic militants who are fighting to make India's part of Kashmir independent or unite it with Pakistan.

India and Pakistan have fought three wars since the subcontinent was partitioned at independence from Britain in 1947, two over Kashmir, but they have been pursuing efforts to improve relations and ease tensions since early last year.

"Both India and Pakistan internalized the experience of the last few years. This is reflected in the sobriety" of official comments about the bombings, said C. Uday Bhaskar, an analyst at New Delhi's Institute for Defense Studies and Analyses.

He noted that after the bloody 2001 attack on parliament, Indian leaders quickly blamed Kashmir militants and Pakistan's spy agency, nearly bringing on another fourth war.

"We now have a better appreciation of the linkages in such terror attacks and a better assessment of how to articulate it in public," Bhaskar said.

This time, too, Pakistan's government has been quick to condemn the bombings, which drew worldwide condemnation.