The Israeli military launched airstrikes on more than a dozen Hamas targets early Sunday after it said militants broke an informal ceasefire by firing projectiles toward Israeli communities. Sirens blared in southern Israel throughout the night to warn of incoming rockets, though there were no reports of injuries on either side. The Israeli military said some of the projectiles fired by Hamas were intercepted and others landed in Gaza. Fifteen Hamas targets were hit in retaliatory strikes, including military compounds and munition factories, Israel said. The flare-up in violence comes after a 21-year-old Palestinian medic was shot dead by Israeli forces while tending to the wounded Friday at a protest along the border with Gaza.