India and Pakistan agreed to an immediate ceasefire on Saturday, unexpectedly halting the worst fighting in decades between the nuclear-armed neighbors, just when their tit-for-tat strikes appeared to be spiraling out of control.

The sudden announcement of a U.S.-brokered ceasefire followed four days of steady escalation between India and Pakistan and mixed signals from Washington.

India and Pakistan on Saturday agreed to a ceasefire following U.S.-led talks to end the most serious military confrontation between the nuclear-armed rivals in decades.