With the risk of dangerous escalation between India and Pakistan the highest in decades, only international mediation can stop a spiral into all-out conflict between the nuclear-armed foes, analysts say.

Pakistan said it launched counterattacks on Saturday after India struck three of its air bases overnight following days of missile, artillery and drone strikes across the border.

It is the first time since the India-Pakistan war of 1971 — before both got nuclear weapons — that they have struck deep inside each other's territory, reaching as far as Karachi on the Arabian Sea coast.