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 ceasefire follows weeks of clashes that were triggered by a gun massacre on tourists last month that India blames on Pakistan. The first word on the truce came from U.S.

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.