BEIRUT — Israeli warplanes bombed the outskirts of Damascus early Sunday for the second time in recent days, according to Syrian state media and reports from activists, signaling a sharp escalation in tensions between the neighboring countries that had already been exacerbated by the conflict raging in Syria.

Though there was no official confirmation that Israel had carried out the attack, the Israeli military later announced that it had deployed two of its Iron Dome rocket defense batteries near itsnorthern border, in response to what it called “ongoing situational assessments.