Syria's allies have condemned an Israeli air strike inside Syria, with Iran threatening grave consequences.
Syria has also formally complained to the United Nations over the reported attack.
The army says Israeli jets targeted a military research centre in Jamraya, north-west of the capital Damascus on Wednesday, killing two people and wounding five.
It denied claims by the United States and others that trucks carrying weapons bound for Lebanon were hit.
Iran's deputy foreign minister warned Israel would suffer grave consequences for the strike and not to have faith in its anti-missile defence system.
The ABC reports that could be a reference to possible retaliation by Hizbollah, which is backed by Syria and Iran and has missiles stationed in Lebanon just across the border with Israel.
There is confusion about the target of the attack, because a Western diplomat and Lebanese security officials told international news agencies that Israel hit an arms convoy probably carrying advanced SA-17 surface-to-air missiles to Hizbollah.
Israel has made no comment.
Lebanese military and internal security forces say there has been increased activity by Israeli warplanes over Lebanon in the past week, particularly on Tuesday and early on Wednesday morning.
The BBC reports that Israel is also concerned that Hizbollah could obtain anti-tank and anti-aircraft missiles, thus strengthening its ability to respond to Israeli air strikes.
Israel believes Syria received a battery of SA-17s from Russia after a Syrian nuclear reactor near Deir Ezzor in eastern Syria was destroyed by an air strike in 2007.