BEIRUT, Lebanon — A series of powerful explosions rocked the outskirts of Damascus early Sunday morning, which Syrian state television said was the result of Israeli missile attacks on a Syrian military installation.

If true, it would be the second Israeli airstrike in Syria in two days and the third this year.

The airstrike that Israeli warplanes carried out in Syria overnight on Thursday was directed at a shipment of advanced surface-to-surface missiles from Iran that Israel believed was intended for Hezbollah, American officials said Saturday. That strike was aimed at disrupting the arms pipeline that runs from Syria to Hezbollah, the militant Lebanese organization, and it highlighted the mounting stakes for Hezbollah and Israel as Syria becomes more chaotic.

Iran and Hezbollah have both backed President Bashar al-Assad in the Syrian civil war, now in its third year. But as fighting in Syria escalates, they also have a powerful interest in expediting the delivery of advanced weapons to Hezbollah in case Mr. Assad loses his grip on power and Syria ceases to be an effective channel for funneling weapons from Iran.

The missiles that were the target of the Israeli raid had been shipped from Iran and were being stored in a warehouse at Damascus International Airport when they were struck, according to an American official.