Pakistan's military has shot down an Indian drone along the de facto Kashmir border, state radio in Islamabad reported, a week after the deadliest attack on civilians in the contested region in years.

The Indian army also said on Tuesday that both sides exchanged fire for a fifth straight night along the Line of Control (LoC), a heavily fortified zone of high-altitude Himalayan outposts.

There was no immediate confirmation from Pakistan on the exchange of fire, as the state broadcaster Radio Pakistan reported that the military had shot down an Indian "quadcopter", calling it a violation of its airspace.

It did not say when the incident happened. There was no comment from New Delhi.

Relations between the nuclear-armed neighbours have plummeted after India accused Pakistan of backing an attack in India-administered Kashmir on April 22 in which 26 men were killed.

Islamabad has rejected the charge, and both countries have since exchanged gunfire in Kashmir, diplomatic barbs, expelled citizens and ordered the border shut.

The unmanned Indian aircraft had attempted to conduct surveillance along the LoC in the Manawar Sector of the Bhimber area, the Radio Pakistan report said.

'Exercise restraint'

India said the "Pakistan Army resorted to unprovoked small arms firing across the Line of Control" overnight from Monday to Tuesday. The gunfire took place in areas opposite Kupwara and Baramulla districts, as well as in the Akhnoor sector, it said.

India has said Tuesday is the deadline for Pakistani citizens to leave.

Muslim-majority Kashmir has been divided between India and Pakistan since their independence from British rule in 1947. Both claim the territory in full.

Rebels in the Indian-run area have waged an insurgency since 1989, seeking independence or a merger with Pakistan.

Indian police have issued wanted posters for three men – two Pakistanis and a Kashmiri.

The United Nations has urged the arch-rivals to show "maximum restraint", while China, which shares a border with both India and Pakistan, repeated its call on both sides to "exercise restraint".