The G7 group of nations called for "immediate de-escalation" and "maximum restraint" in the conflict between India and Pakistan as the nuclear-armed neighbours spiralled toward full-blown war.

"Further military escalation poses a serious threat to regional stability," the foreign ministers of the seven wealthy democracies said in a statement on Friday, adding that both sides should "engage in direct dialogue towards a peaceful outcome".

However, state-run Pakistan Television said on Saturday that retaliatory attacks are under way after India fired missiles at three air bases inside Pakistan.

It did not give details, and it was unclear which military locations in India were being targeted.

“Multiple locations in India are being targeted in the retaliatory attacks,” the state-run media reported.

The Pakistani military said it used medium-range Fateh missiles to target an Indian missile storage facility and airbases in Pathankot and Udhampur.

Pakistani army spokesman, Lt Gen Ahmad Sharif, said in a televised address that the country's air force assets were safe following the Indian strikes. He added that some of the Indian missiles also hit India’s eastern Punjab.

“This is a provocation of the highest order,” Sharif said.

Tensions between the nuclear-armed rivals have soared since an attack at a popular tourist site in India-controlled Kashmir left 26 civilians dead, mostly Hindu Indian tourists, on April 22. New Delhi has blamed Pakistan for backing the assault, an accusation Islamabad rejects.

The Indian missiles targeted Nur Khan air base in the garrison city of Rawalpindi, near the capital Islamabad, Murid air base in Chakwal city and Rafiqui air base in the Jhang district of eastern Punjab province, according to the spokesman.

Sharif said some of the Indian missiles also went into Afghanistan.

“I want to give you the shocking news that India fired six ballistic missiles from its city of Adampur," said Sharif. One of the ballistic missiles hit Adampur, the remaining five missiles hit the Indian Punjab area of Amritsar."

Residents in Indian-controlled Kashmir said they heard loud explosions Saturday at multiple places in the region, including the two big cities of Srinagar and Jammu, and the garrison town of Udhampur.

“Explosions that we are hearing today are different from the ones we heard the last two nights during drone attacks,” said Sheesh Paul Vaid, the region’s former top police official and a resident of Jammu. “It looks like a war here.” (Agencies)