Pakistan's military says it has launched retaliatory strikes on sites in India, alarming world powers about further hostilities between the nuclear nations.

Pakistan said it had fired missiles at military sites in India after accusing India of targeting at least three of its air bases. India said it had targeted the bases in response to a wave of Pakistani attacks.

Blasts rang out across Indian Kashmir and the Sikh holy city of Amritsar in neighbouring Punjab state late on Friday, with the Indian military saying it was shooting down drones in the worst fighting with Pakistan in nearly three decades.