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.

Blasts were heard in Srinagar and Jammu and projectiles and flashes were seen in the night sky over Jammu, similar to the events of the previous evening, according to authorities, residents and Reuters witnesses.

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