NEW DELHI/ISLAMABAD, 15 December — Tension mounted between archrivals India and Pakistan in the wake of Thursday’s suicide attack on Indian parliament with New Delhi blaming a Pakistan-based group for the attack and Islamabad threatening tough action in case of a "misadventure."

India said yesterday it had evidence that Pakistan-based Lashkar-e-Taiba members were behind the attack and demanded that Islamabad arrest their leaders and freeze their assets. The announcement is likely to fuel demands within the ruling Hindu nationalist BJP party that the government carry out punitive raids against alleged terrorist training camps in Pakistan-administered Kashmir.

Foreign Minister Jaswant Singh told reporters India had technical evidence that the attack was carried out by Lashkar activists.

Five heavily armed gunmen had stormed the Indian parliament complex Thursday morning, killing seven people before they were shot dead.

Lashkar later described New Delhi’s accusations as "baseless," while Pakistan warned India against taking any rash action. "India seems to be making efforts to create tension by blaming Pakistan," said military government spokesman Maj. Gen. Rashid Qureshi. "India will pay heavily if they engage in any misadventure."

Pakistani government, meanwhile, promised to examine what India called "technical evidence" it had about the alleged involvement of the Lashkar group.

"If India provides us with evidence, we will examine it," the official Associated Press of Pakistan (APP) news agency quoted Foreign Ministry spokesman Aziz Ahmed Khan as saying.

Islamabad had condemned Thursday’s attack on the Indian parliament and President Pervez Musharraf sent condolences to Indian Prime Minister Atal Behari Vajpayee.

Singh said the Pakistani high commissioner (ambassador) to India had been summoned and told that his government should take immediate action against the Lashkar, and another hard-line militant group, Jaish-e-Muhammad. Singh said the specific demands were for the activities of both groups to be halted in Pakistan.

"Secondly that their leadership which is known to Pakistan be taken in custody. Thirdly that the financial assets and access to financial assets by these organizations be stopped."

India has blamed the Lashkar for previous attacks on high-profile targets, including an armed raid on the historic Red Fort in New Delhi in December last year.

Singh said the technical evidence had been shown to several other countries including the United States.

Asked if there was any suspicion of direct Pakistani government involvement in Thursday’s attack, Singh said it was simply a question of reflecting on the "origins, funding and patronage" of groups like Lashkar and Jaish.

Chief BJP spokesman V.K. Malhotra said party MPs had met Prime Minister Vajpayee yesterday and urged him to "adopt a pro-active and hot pursuit policy and destroy terrorist camps in Pakistan-administered Kashmir, whether through land or by air."

"The way the United States went into Afghanistan, the government should also take similar steps," Malhotra said.

Hard-line elements within Vajpayee’s BJP-led coalition have long been pushing for a policy shift in Kashmir, which would allow security forces to pursue militants over the Line of Control (LoC) dividing the Indian- and Pakistani-controlled zones of the divided Himalayan region.

Questioned later by reporters, Vajpayee refused to comment on whether such a policy change was being envisaged. "I can’t answer this question now," he said.

India needs some time to decide how to react, Vajpayee said.

The spokesman for the main opposition Congress party, Jaipal Reddy, warned of the dangers of punitive raids against a nuclear-armed power such as Pakistan.

"We should not go for hot pursuit. America went into Afghanistan because it was not a nuclear state," Reddy said.

Addressing a civil service function earlier in the day, Vajpayee said Thursday’s attack had been "an arrogant challenge" to democracy worldwide.

"We have resolutely been countering every new manifestation of terrorism in our country. We shall repulse this one equally firmly," he said.

Rajinder Bhullar, the intelligence chief of India’s Border Security Force in Kashmir said the methods used by the five gunmen on Thursday were strongly suggestive of the Lashkar-e-Taiba.

In parliament, lawmakers, past and present, embraced each other as they walked up the front steps of the sandstone parliament building where a suicide bomber blew himself up in Thursday’s attack.

"Today we are one, we are united in this battle against terrorism, we will fight back," said Renuka Chowdhary, a deputy from the Congress party.