Iran has threatened Israel with "grave consequences" after Israeli jets reportedly bombed a Syrian military complex near Damascus.
, on the outskirts of the Syrian capital, at dawn on Wednesday.
But a Western diplomat and Lebanese security officials told international news agencies that the attack actually hit an arms convoy, probably carrying advanced surface-to-air missiles to Hezbollah, near the border with Lebanon.
Adding to the confusion, a local rebel group said it was responsible for the attack, which involved mortar fire on the weapons compound.
Iran's deputy foreign minister Hossein Amir Abdollahian said the attack clearly demonstrated that foreign-sponsored militants and Israel "pursue the same goals with regard to Syria", and warned Israel not to have faith in its anti-missile defence system.
That could be a reference to possible retaliation by Hezbollah, which is backed by Syria and Iran, and has missiles stationed in Lebanon, just across the border with Israel.
Meanwhile, Syria has called in the commander of the United Nations force which observes a decades-old truce between Syria and Israel.
The Syrian foreign ministry says it lodged an official protest over Israel's violation of the agreement, which dates back to 1974.
UN secretary-general Ban Ki-Moon has expressed grave concern, and urged all concerned to abide by international law.
Russia says if the strike is confirmed it would be "a very serious breach of the UN charter".
Israel has made no comment.