Pakistan says it has shot down two Indian military jets and captured two pilots in a major escalation between the nuclear powers over Kashmir.
Pakistani PM Imran Khan said the two sides could not afford a miscalculation with the weapons they had.
India and Pakistan – both nuclear-armed states – claim all of Kashmir, but control only parts of it.
They have fought three wars since independence from Britain and partition in 1947. All but one were over Kashmir.
The aerial attacks across the Line of Control (LoC) dividing Indian and Pakistani territory are the first since a war in 1971.
They follow a militant attack in Kashmir which killed 40 Indian troops - the deadliest to take place during a three-decade insurgency against Indian rule in Kashmir. A Pakistan-based group said it carried out the attack.
The BBC says the challenge for India and Pakistan now is to contain the latest escalation before things spin out of control.
Pakistan's information ministry published but subsequently deleted a video purporting to show one of the Indian pilots that the Pakistani military says it has captured.
In the video, the pilot – who is blindfolded and appears to have blood on his face – identifies himself as Wing-Commander Abhinandan.
The ministry also tweeted what it said was footage of one of the downed Indian jets.