An Indian minister said the weekend bomb attacks that claimed 62 lives in New Delhi would not affect peace talks with Pakistan despite the hints by Manmohan Singh.

"The Delhi serial blasts will have no effect on the ongoing peace process between India and Pakistan," junior home minister Sri Prakash Jaiswal told reporters in the northern town of Sultanpur, the Press Trust of India news agency reported.

Detectives were hunting for a casually-dressed unshaven man in his twenties, whom witnesses saw slipping off a bus after leaving a bag which exploded minutes later in the Okhla industrial area, police sources were quoted as saying.

A rough sketch of the suspected bomber has been prepared with the help of a passenger who sat next to him and interacted with him briefly. All passengers were saved after the bus driver threw out the abandoned bag.

Police said bags used in Saturday's two other blasts which killed 62 people -- in the Sarojini Nagar and Paharganj markets -- were of similar make and they were questioning shopkeepers in the hope of identifying the purchasers.

Investigators also said 60-minute timer devices were used and traces of Research Developed Explosive (RDX) have been found in the bomb devices, which can usually be assembled only by teams of experts.

Karnail Singh, the head of New Delhi's anti-terrorism unit, said the attacks were probably coordinated by a single organisation but were carried out by different units of the group.

"They targeted chaat shops (snack food stalls) at both Paharganj and Sarojini Nagar markets as they are generally crowded with women and children. The target was maximum damage," he said.

Fireworks, meanwhile, exploded across the city from early Tuesday as Hindus celebrated Diwali, the festival of lights, while police kept a tight watch on markets, temples and public places.

The city, which has brought in 2,600 security personnel to bolster its 71,000-member police force, remained on high alert.

Main festivities were due in the evening when family members visit temples to offer prayers before gathering at home to explode fireworks deep into the night.

Markets, which had been emptier than usual immediately after the blasts, were filled Monday night and early Tuesday with people stocking up with food, candles, strings of flashing lights and fireworks.

Prime Minister Singh, meanwhile, indicated the possibility of Pakistani involvement in Saturday's blasts.

"We continue to be disturbed and dismayed at indications of the external linkages of terrorist groups with the October 29 bombing," Singh said in a telephone call late Monday initiated by Pakistani President Pervez Musharraf.

"India expects Pakistan to act against terrorism directed at India," Singh told Musharraf during their 10-minute telephone conversation, a foreign office statement said.

"The prime minister again drew the president's attention to Pakistan's commitment to ending cross-border terrorism," the statement said. Musharraf made the commitment in January 2004.

Pakistan rejected Singh's comments and called on him to produce evidence. "Unless they share the evidence with us, it remains a mere claim which we cannot accept," said foreign ministry spokeswoman Tasnim Aslam.

In a statement on Sunday a man claiming to be the spokesman for the Islamic Revolutionary Group said the attacks would continue as long as Indian troops remained in Kashmir.

Police have said the group was created in 1996 and had links to Lashkar-e-Taiba, a pan-Islamic group which has been involved in a number of deadly attacks -- including in Kashmir where an anti-Indian insurgency has been raging since 1989.

A spokesman for the Pakistani-based militant group, Lashkar-e-Taiba, called accusations of its involvement "completely baseless and false."

In a phone call to a news agency in Indian Kashmir, the spokesman who identified himself as Abu Huzaifa said his group, which has carried out dozens of attacks in the past, does not target civilians.

India accuses Pakistan of arming, aiding and training Islamic rebel groups battling New Delhi's rule in Indian Kashmir, a charge Islamabad denies.

India blamed Lashkar for an attack on the country's parliament in December 2001 which left 15 people dead, including five attackers.

The insurgency has claimed at least 44,000 lives in Kashmir, which is ruled in part but claimed in full by both India and Pakistan. The nuclear-armed rivals have fought two wars over the Himalayan territory.