Indian and Pakistani troops exchanged gunfire for a second straight day on Saturday as ties plummeted between the two nuclear-armed neighbours after an attack on tourists blamed on Pakistani militants killed 26 in India-administered Kashmir.

The Indian Army said its troops responded to "unprovoked" small arms fire from multiple Pakistan Army posts that started around midnight on Friday along the 740-km (460-mile) Line of Control (LoC) in the area.

The Indian Army said Pakistani troops had also opened up with sporadic fire around midnight on Thursday. No casualties were reported from the Indian side, it said.

There was no immediate comment from the Pakistani military.

Police in Indian-administrated Kashmir have identified three suspects, including two Pakistani nationals, who carried out the April 22 attack.

Pakistan has denied any involvement and its defence minister has said an international investigation was needed into the attack.

After the attack, India and Pakistan unleashed a raft of measures against each other, with Pakistan closing its airspace to Indian airlines, and India suspending the 1960 Indus Waters Treaty that regulates water-sharing from the Indus River and its tributaries.

India and Pakistan have a decades-old ceasefire agreement over the disputed region of Kashmir but their troops still exchange gunfire sporadically. The two nations both claim Kashmir and have fought two of their three wars over it.