Why are India and Pakistan on the brink of war? Here's what the fighting in Kashmir is all about.

New Delhi — A deadly terrorist attack in Indian-administered Kashmir's picturesque Pahalgam area in April has brought India and Pakistan once again to the brink of war. The nuclear armed South Asian neighbors have attacked each other this week with missiles and drones in a sudden flare-up of a decades-old feud that's being watched with concern by leaders around the world. 

The bitter rivals have fought three wars over Kashmir in the past, and once again they're warning each other against any moves that could escalate the tension — and vowing to respond in kind to any such moves with tough military action.

After a week of intense clashes, air raid sirens blared in a couple Indian cities near the Pakistani border on Friday and authorities asked people to remain indoors. Officials said a woman was killed and four men injured in alleged Pakistani cross-border fire in the Kashmiri town of Uri, while all major airports and the capital city of Delhi were on high alert, with some schools shut and major landmarks evacuated.