Israel says it had attacked Iranian targets in Syria to foil an imminent attack by what it called Iranian "killer drones" on Israel.
Despite Iranian denials of the attack, the incident has sparked new tensions between Israel and Iran. Israel ordered deployment of its Iron Dome missile to its border with Syria.
It is rare that Israel takes responsibility for air strikes on Iranian targets in Syria, although Israel is believed to have carried out hundreds of these attacks over the past few years. But this time Prime Minister Benjamin Netanyahu took credit in a tweet that praised the army's major operational effort and said that Iran had planned to send killer drones with explosives into Israel. He warned Iran that it had "no immunity anywhere."
The Israeli army said that four Iranian operatives had recently arrived in Syria to pilot so called Kamikaze drones, each armed with explosives.
The Syrian Observatory for Human Rights reported that five people were killed including two fighters from the pro-Iranian Lebanese Hezbollah organization. However, the Reuters news agency quoted a senior Iranian official Mohsen Rezai, that Israel does not have the capability to do this type of attack.
Israeli cabinet minister Tzachi Hangebi said Israel acted on its intelligence to thwart an imminent attack.
He said that Israel had been watching a specific site in Iran closely and knew that the attack was planned to set out from there.
Former Israeli national security advisor Yakov Amidror said that Israel is concerned about Iran's growing strength in Syria.
"Israel is now in the middle of a long effort to stop the Iranians from building their independent war machine in Syria. They had one in Lebanon controlled by Hebollah and they want to build an independent one in Syria which would be controlled by Iran," he said.
Israel has moved anti-missile batteries called the Iron Dome system to its northern border in case of Iranian missile strikes on Israel.
Meanwhile, Hezbollah says two Israeli drones have crashed in Lebanon overnight.
The second drone fell on a building that houses Hezbollah's media center in the Dahyeh suburbs of Lebanon's capital, Beirut.
"We did not shoot down or explode any of the drones," Hezbollah spokesman Mohammed Afif told the Associated Press.
Israel has not commented on the drone strike.