Israeli aircraft on Saturday night struck Iranian forces near Damascus that had been planning to launch "killer drones" at targets in Israel, the IDF said in a statement.
"The strike targeted Iranian Quds Force operatives and Shiite militias that had been preparing advance attacks targeting sites in Israel from within Syria," IDF spokesman Jonathan Conricus said.
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Conricus added that Israel had monitored the plot for several months and on Thursday prevented Iran from making an "advanced attempt" to execute the same plan. Then, Iran tried again late on Saturday to carry out the same attack, he said.
"We were able to thwart this attack with fighter jets," he said, saying that the Iranian attack was believed to be "very imminent."
He said that IDF Chief of Staff Lt. Gen. Aviv Kochavi was meeting with senior officers and forces were on high alert near the Syrian border.
War monitor the Syrian Observatory for Human Rights said two members of Hezbollah and were killed as well as three other members of a pro-Iranian militia.
A senior IRGC commander denied that Iranian targets had been hit, the semiofficial Iranian Labour News Agency reported.
"This is a lie and not true. Israel and the United States do not have the power to attack Iran's various centers, and our [military] advisory centers have not been harmed," Maj. Gen. Mohsen Rezaei, who is also the secretary of a powerful state body, ILNA reported.
Iran's Quds Force is the overseas arm of Iran's Iranian Revolutionary Guard Corps.
Prime Minister Benjamin Netanyahu said that the IDF had thwarted the planned Iranian attack. "Iran has no immunity anywhere. Our forces operate in every sector against the Iranian aggression," he said on Twitter.
Shortly after the strike near Damascus, an Israeli drone reportedly crashed into the Hezbollah-dominated southern suburbs of Beirut and a second one exploded near the ground on Sunday, a Hezbollah official told Reuters.
The IDF said it does not comment on foreign reports.
The second drone caused some damage when it crashed before dawn close to Hezbollah's media center in the Dahiyeh suburbs of the Lebanese capital, the Hezbollah official said.
Residents in Dahiyeh said they had heard the sound of a blast. A witness said that the Lebanese army closed off the streets in one neighborhood where a fire had started. No other information was immediately available.
Hezbollah spokesman Mohammed Afif said a small, unmanned reconnaissance drone fell on a building housing Hezbollah's media office in the Moawwad neighborhood in Dahiyeh.
He said a second drone, which appeared to have been sent by Israel to search for the first one less than 45 minutes later, exploded in the air and crashed in an empty plot nearby, causing damage to nearby buildings. Residents said they heard a loud blast.
"We did not shoot down or explode any of the drones," Afif told The Associated Press.
He said Hezbollah leader Hassan Nasrallah will give the "appropriate" response in a previously-scheduled televised appearance later Sunday.
Back in Damascus, Syrian state media said the military's air defenses had intercepted "hostile targets" over the capital.
Witnesses in Damascus said they heard and saw explosions in the sky.
The Syrian army said in a statement that "the majority of the Israeli missiles were destroyed before reaching their targets."
Conricus, however, said that the impact of the Israeli strikes was "significant."
Israel says it has carried out hundreds of strikes in Syria against Iranian targets, which are trying to establish a permanent military presence there and against advanced weapons shipments to Hezbollah.
Iran and Hezbollah are helping Syrian President Bashar Assad in the eight-year-long Syria war. Russia, which is also aiding Assad, has largely turned a blind eye to the Israeli airstrikes. Netanyahu spoke with Russian President Vladimir Putin on Friday, the Prime Minister's Office said.
On Thursday, Netanyahu hinted of possible Israeli involvement in a series of blasts in the past few weeks that have hit weapon depots and bases belonging to paramilitary groups in Iraq, many of them backed by Iran.
On Wednesday, the PMF, the umbrella grouping of Iraq's mostly Shiite Muslim paramilitary groups, said that the United States had allowed four Israeli drones to enter the region while accompanying US forces and carry out missions in Iraqi territory.
