Israeli warplanes struck areas in and around the Syrian capital Sunday, setting off a series of explosions as they targeted a shipment of highly accurate, Iranian-made guided missiles believed to be bound for Lebanon's Hezbollah militant group, officials and activists said. The attack, the second in three days and the third this year, signaled a sharp escalation of Israel's involvement in Syria's bloody civil war. Syrian state media reported that Israeli missiles struck a military and scientific research center near Damascus and caused casualties. Syria's government called the attacks against against its territory a "flagrant violation of international law" that has made the Middle East "more dangerous" and warned it has the right "to defend its people by all available means." The generally muted response, read out by the information minister after an emergency government meeting, appeared to signal that Damascus did not want the situation to escalate. Instead, it tried to use the strikes to taint the rebels, claiming the attacks were evidence of an alliance between Israel and Islamic extremist groups trying to overthrow President Bashar Assad. The air raids pose a dilemma for a regime already battling a relentless rebellion at home. Failure to respond could make it look weak and open the door to more strikes. But any military retaliation against Israel would risk dragging the Jewish state and its powerful army into a broader conflict. The tempo of the new strikes added a dangerous dynamic to the conflict, fueling concerns that events could spin out of control and spark a regional crisis. Israel's military on Sunday deployed two batteries of its Iron Dome rocket defense system to the north of the country. It described the move as part of "ongoing situational assessments." A senior Israeli official, who spoke on condition of anonymity in order to disclose information about a secret military operation to the media, confirmed that Israel launched an airstrike in the Syrian capital early Sunday but did not give more precise details about the location. The target was Fateh-110 missiles, which have precision guidance systems with better aim than anything Hezbollah is known to have in its arsenal, the official told The Associated Press. The airstrikes come as Washington considers how to respond to indications that the Syrian regime may have used chemical weapons in its civil war. President Barack Obama has described the use of such weapons as a "red line," and the administration is weighing its options — including possible military action.