Israel carried out an air strike targeting a shipment of missiles in Syria bound for Iran-backed Hezbollah in Lebanon, Israeli officials said on Saturday.
The Israeli officials spoke on condition of anonymity because they were not authorized to disclose information about a secret military operation to the media.
Theys said the attack took place early Friday and was aimed at sophisticated "game-changing" weapons, but not chemical arms.
One official said the target was a shipment of advanced, long-range ground-to-ground missiles.
It was not immediately clear where the attack took place, or whether the air force carried out the strike from Lebanese or Syrian airspace.
The Israeli officials spoke on condition of anonymity because they were not authorized to disclose information about a secret military operation to the media.
U.S. officials had earlier confirmed the airstrike but said only that it appeared to have hit a warehouse.
Israel had long made clear it is prepared to resort to force to prevent Syrian weapons, including President Bashar al-Assad's chemical arsenal, reaching Hezbollah allies or Islamist rebels taking part in a more than two-year-old uprising against his government.
In January, the Israeli air force is believed to have targeted a shipment of advanced SA-17 anti-aircraft missiles bound for Hezbollah. Israel has not formally admitted to carrying out that airstrike, though officials have strongly hinted they were behind the attack.
President Assad has long had a close relationship with Hezbollah, and Syria has been a gateway for shipping Iranian weapons to the Lebanese group.
Hezbollah has sent trainers and advisers to Syria to help Assad’s regime with his war against the Syrian opposition. Syrian opposition officials report that Hezbollah fighters are also involved in the conflict.