Israeli warplanes bombed targets in territory held by the Syrian government near Damascus on Sunday, underscoring the deepening complexity of the war raging on multiple fronts in Syria and beyond.

Israel has carried out airstrikes in Syria on at least four occasions since early 2013, but these were the first attacks in many months and the first since the United States began bombing Syria in September.

Whereas the U.S. raids have targeted positions of the extremist Islamic State and Jabhat al-Nusra, however, the Israeli ones have all been carried out against government facilities in areas loyal to Syrian President Bashar al-Assad.

Israel has made no official comment on strikes it has conducted in the past and did not comment on Sunday’s bombings, which were reported by Syrian state media and opposition activists.

The exact targets of the strikes weren’t clear, but a statement from the Syrian army’s general command said Damascus International Airport and another site in the Damascus countryside were hit. Syrian journalists and activists said the second site was a small civilian airport in Dimas, northwest of the capital on the road to Lebanon. The Syrian Observatory for Human Rights said an import-export warehouse was the target of the attack on the international airport.

Previous Israeli strikes appear to have been aimed at deterring shipments of Iranian missiles and other weaponry to the Lebanese Shiite Hezbollah movement. Sunday’s raids were probably no different, said Jeff White of the Washington Institute for Near East Policy.

Israeli officials have repeatedly said Israel will not hesitate to strike to prevent advanced weaponry from reaching Hezbollah in Lebanon, where Hezbollah and Israel fought a brief but fierce war in 2006 and where border tensions have risen in recent months.

“This is part of an Israeli pattern where, when they see a shipment of destabilizing arms going to Hezbollah, they strike,” White said. The bombing raids had less to do with the dynamics of Syria’s war than “with the Israeli-Hezbollah equation,” he added.

The Syrian army’s statement, however, said the raids were aimed at “raising the morale of terrorist organizations, including the Al Qaeda-affiliated Jabhat al-Nusra and ISIS” — an acronym for the Islamic State.

The Israeli attacks followed a failed Islamic State offensive to recapture the government-held airport in the eastern city of Deir el-Zour over the weekend. They were also the first since Jabhat al-Nusra fighters, alongside other rebel groups, seized control of positions on Syria’s disputed border with Israel in the Golan Heights in September.

Syrian state media said there were no casualties Sunday. There was no indication that Syrian air defenses sought to engage the attackers, although the army statement called the strikes “an act of aggression.”

Israel and Syria have been in a state of war since 1948, but Syria has avoided confronting its more powerful adversary since Israel’s invasion of Lebanon in 1982. It has moreover demonstrated no appetite for confronting Israel since the rebellion against Assad erupted in 2011, embroiling Syria’s military in the effort to crush the revolt.

Hezbollah fighters have played a vital role in helping Assad’s depleted security forces prevail over the rebels. Assad has also been a beneficiary of the U.S. strikes against the extremists, which have freed up his forces to battle moderate rebels elsewhere.