Khan used a nationally televised address to demand Delhi share proof of Islamabad's alleged involvement in last week's suicide blast, which killed 41 people in Indian-held Kashmir and unleashed a fresh diplomatic crisis over the disputed Himalayan region.

The attack, which has triggered nationwide anger in India, was claimed by Pakistan-based militant group Jaish-e-Mohammed.

Indian officials have said those behind the blast will pay a "heavy price". The Indian military also said Tuesday the bombing had been "masterminded" by Pakistan, and specifically its powerful Inter-Services Intelligence branch.

If India attacks, "Pakistan won't just think to retaliate. Pakistan will retaliate," said Khan in the address.

Islamabad has denied involvement. "If you have some actionable intelligence about involvement of Pakistanis, give it to us, I guarantee you that we will take action," Khan said Tuesday, adding that Pakistan was "ready to talk" about terrorism with India.

It was "easy to start a war", he said, adding that he hopes "better sense will prevail".

Kashmir has been split between India and Pakistan since independence from Britain in 1947. Both countries claim the Himalayan territory in full and have fought two wars in connection to the dispute.

India has long accused Pakistan of harbouring militants that launch attacks on its soil, including banned groups such as JeM and Lashkar-e-Taiba, blamed for carrying out the 2008 Mumbai attacks which left scores dead.

Islamabad has repeatedly vowed to crack down on the groups if Delhi provides evidence of involvement.

Khan said on Tuesday that if any militant group was using Pakistani soil to launch attacks, "its enmity is with us. This is against our interest".

Pakistan was also accused by Iran last week of sheltering the perpetrators of an attack which killed 27 Revolutionary Guards, while Kabul and Washington have long claimed that Islamabad offers safe haven to the Afghan Taliban.

- 'Defuse tensions' -

With anger building in India, Prime Minister Narendra Modi faces increased pressure to act as his Hindu nationalist government is expected to call a national election within weeks.

Indian forces have staged operations since Thursday's attack while anti-Pakistan and anti-Kashmir sentiment has spread across the country, fuelled by social media including widely shared false news reports.

On Tuesday the Indian army said three JeM militants were killed in a gun battle a day earlier.

Two of them were Pakistanis, including the group's "chief operations commander in Kashmir", Lieutenant General Kanwal Jeet Singh Dhillon told a press conference in Srinagar.

The Indian government has already withdrawn trade privileges for Pakistan, ended police protection for four Kashmiri separatist leaders, and halted some cross-border services.

Earlier Tuesday, Pakistani Foreign Minister Shah Mahmood Qureshi pleaded with UN Secretary General Antonio Guterres to intervene in the escalating row.

"The United Nations must step in to defuse tensions," wrote Qureshi in a message shared with journalists.

On Monday Saudi Arabia vowed to "de-escalate" the situation during a high-profile state visit by Crown Prince Mohammed bin Salman to Islamabad. He is also due in India this week.

Kashmir is one of the world's most militarised zones, with some 500,000 Indian troops deployed to fight a rebellion that broke out in 1989.

Scores of armed groups are now involved.

Tens of thousands of people, mainly civilians, have died in the conflict. Violence has spiked since 2016 with almost 600 killed last year, the highest toll in a decade.

Pakistan's ambassador to Afghanistan warned that any action by Delhi against Islamabad could disrupt peace talks with the Taliban.

Pakistan is "playing a very important role" in the months-long push led by the US for talks between the Taliban and the Afghan government, said Zahid Nasrullah. A fresh round of negotiations is set to begin next week.