BEIRUT — Israel signaled a return to "business as usual" on Monday, a day after its aircraft struck targets in Syria for the second time in 48 hours in an unprecedented escalation of Israeli involvement in the Syrian civil war.
Prime Minister Benjamin Netanyahu left Israel after a meeting of his security Cabinet and arrived in China for a scheduled visit on Monday, a possible indication that Israel does not expect an immediate retaliation.
Syria and its patron Iran have hinted at possible retribution for the strikes, though the rhetoric in official statements has been relatively muted.
Still, the back-to-back airstrikes, though not officially acknowledged by the Israeli government, raised new concerns about a regional war.
Israeli officials have indicated they will keep trying to block what they see as an effort by Iran to send sophisticated weapons to Lebanon's Hezbollah militia ahead of a possible collapse of Syrian President Bashar Assad's regime.
Israel has repeatedly threatened to intervene in the Syrian civil war to stop the transfer of what it calls "game-changing" weapons to Hezbollah, a Syrian-backed group that battled Israel to a stalemate during a war in 2006.
Since carrying out a lone airstrike in January that reportedly destroyed a shipment of anti-aircraft missiles headed to Hezbollah, Israel had largely stayed on the sidelines. That changed this weekend with the pair of airstrikes, including an attack near a sprawling military complex close to the Syrian capital of Damascus early Sunday that set off a series of powerful explosions.
A senior Israeli official said both airstrikes targeted shipments of Fateh-110 missiles bound for Hezbollah. The Iranian-made guided missiles can fly deep into Israel and deliver powerful half-ton bombs with pinpoint accuracy. The official spoke on condition of anonymity because he was discussing a covert military operation.
Syria's government called the attacks a "flagrant violation of international law" that has made the Middle East "more dangerous." It also claimed the Israeli strikes proved Israel's links to rebel groups trying to overthrow Assad's regime.
Syria's information minister, Omran al-Zoubi said Syria has the right and duty "to defend its people by all available means."
Tzahi Hanegbi, an Israeli lawmaker who is close to Netanyahu, said Monday that Israel's aim is to "keep advanced weapons from Hezbollah as soon as intentions are exposed and refrain from tension with Syria."
"So if there is activity, then it is only against Hezbollah and not against the Syrian regime," Hanegbi told Israel Radio. "In that context you must see the fact that Israel doesn't officially admit to its operations, and that the prime minister left yesterday for China and (there is) the feeling of business as usual."
Israeli defense officials believe Assad has little desire to open a new front with Israel when he is preoccupied with the survival of his regime.
More than 70,000 people have been killed since the uprising against Assad erupted in March 2011, and Israeli officials believe it is only a matter of time before Assad is toppled.
Still, Israel was taking precautions. Israel's military deployed two batteries of its Iron Dome rocket defense system to the north of the country Sunday. It described the move as part of "ongoing situational assessments."
Hezbollah fired some 4,000 rockets into Israel during the 2006 war, and Israel believes the group now has tens of thousands of rockets and missiles.
The Iron Dome deployment followed a surprise Israeli drill last week in which several thousand reservists simulated conflict in the north. In another possible sign of concern, Israel closed the airspace over northern Israel to civilian flights on Sunday and tightened security at embassies overseas, Israeli media reported. Israeli officials would not confirm either measure.
Israel's deputy defense minister, Danny Danon, would neither confirm nor deny the airstrikes. He said, however, that Israel "is guarding its interests and will continue to do so in the future."
Israeli defense officials have identified several strategic weapons that they say cannot be allowed to reach Hezbollah. They include Syrian chemical weapons, the Iranian Fateh-110s, long-range Scud missiles, Yakhont missiles capable of attacking naval ships from the coast, and Russian SA-17 anti-aircraft missiles. Israel's airstrike in January destroyed a shipment of SA-17s meant for Hezbollah, according to U.S. officials.
Israeli officials said the Fateh-110s reached Syria last week. Friday's airstrike struck a Damascus airport where the missiles were being stored, while the second series of airstrikes early Sunday targeted the remnants of the shipment, which had been moved to three nearby locations, the officials said.
None of the Iranian missiles are believed to have reached Lebanon, said the officials, who spoke on condition of anonymity because they were discussing a classified intelligence assessment.
The attacks pose a dilemma for the embattled Assad regime.
If it fails to respond, it looks weak and opens the door to more airstrikes. But any military retaliation against Israel would risk dragging the Jewish state and its powerful army into a broader conflict. With few exceptions, Israel and Syria have not engaged in direct fighting in roughly 40 years.
The airstrikes come as Washington considers how to respond to indications 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.
The White House declined for a second day to comment directly on Israel's air strikes in Syria, but said Obama believes Israel, as a sovereign nation, has the right to defend itself.
Iran condemned the airstrikes, and a senior official hinted at possible retribution from Hezbollah.
Gen. Masoud Jazayeri, assistant to the Iranian chief of staff, told Iran's state-run Arabic-language Al-Alam TV that Tehran "will not allow the enemy (Israel) to harm the security of the region." He added that "the resistance will retaliate to the Israeli aggression against Syria."
"Resistance" is a term used for Hezbollah and the Palestinian Hamas, another anti-Israel militant group supported by Iran.
Iran has provided both financial and military support to Hezbollah for decades and has used Syria as a conduit for both. If Assad were to fall, that pipeline could be cut, dealing a serious blow to Hezbollah's ability to confront Israel.
U.N. Secretary-General Ban Ki-moon spoke to Arab League Secretary-General Nabil ElAraby by telephone Sunday and both shared their "grave concern" over the air strikes, U.N. spokesman Martin Nesirky said.
Ban called on all sides "to exercise maximum calm and restraint, and to act with a sense of responsibility to prevent an escalation of what is already a devastating and highly dangerous conflict," Nesirky said.
Federman reported from Jerusalem. Associated Press writer Ian Deitch in Jerusalem contributed to this report.