Israel says it has carried out hundreds of strikes in Syria against Iranian targets trying to establish a permanent military presence there and advanced weapon shipments from Iran's Shiite proxy in Lebanon the Hezbollah terrorist group.
But an Iranian general said the Israeli strikes in Syria did not cause any damage or casualties among Iranian forces there.
The spokesman for the Iran-backed Hezbollah said the group did not fire on any of the drones, which crashed amid heightened tensions between neighbouring Israel and Iran and shortly after Israeli warplanes attacked targets near the Syrian capital, Damascus.
But it rarely acknowledges its actions so swiftly, with Prime Minister Benjamin Netanyahu on Sunday, warning arch-foe Iran it had no immunity from his state's military. Our forces operate in every sector against the Iranian aggression.
A Syrian military source quoted by the state news agency said: "At 2330 (2030 GMT), anti-aircraft defenses detected enemy targets from Golan heading towards the area around Damascus".
Residents in Dahiyeh said they heard the sound of a blast.
The Israeli strike was one of several recent attacks on weapons storage facilities controlled by Iraqi militias with ties to Iran.
It is said to be one of the factors intensifying fighting.
Nasrallah said the strikes actually hit a Hezbollah rest house, marking a rare acknowledgment of member deaths in Syria by Israeli strikes.
Iran and Hezbollah are backing Syrian President Bashar al-Assad's Arab socialist Ba'ath party in the eight-year Syrian civil war. Russia, which also aids Assad, has largely turned a blind eye to the Israeli air strikes.
Lebanon's Hezbollah leader vowed Sunday to shoot down any Israeli drones that enter Lebanese airspace from now on after one allegedly crashed and another exploded in Beirut overnight.
Mohammed Afif, a Hezbollah spokesperson, said the first drone fell onto the roof of the Hezbollah media office in the Dahyeh suburb of the city.
The Popular Mobilisation Forces (PMF), a grouping of Iraq's mostly Shi'ite paramilitary groups, said the United States had allowed four Israeli drones to enter the region accompanying US forces and carry out missions on Iraqi territory.
The US-led coalition, in Iraq to fight remnants of Daesh, dismissed the statement and the Pentagon denied it. Amos Yadlin, a former head of Israeli military intelligence, and now executive director of Tel Aviv University's Institute for National Security Studies (INSS), said neither Iran nor Israel were interested in all-out war.
This has forced Israel to act in Iraq as well as Syria, he said, as the United States is unwilling to undertake action against Iran due to the political situation in Iraq.