The Syrian Observatory for Human Rights says 15 pro-regime fighters were killed in a suspected Israeli strike close to the country's capital Damascus.
Eight Iranians were among 15 foreign pro-regime fighters killed in a suspected Israeli strike in Syria on a weapons depot of Iran's elite Revolutionary Guards, a war monitor said Wednesday.
The raid struck the area of Kisweh south of Damascus late Tuesday, the Britain-based Syrian Observatory for Human Rights monitoring group said.
Syria's official news agency SANA said the army had intercepted two Israeli missiles fired towards Kisweh, with state television broadcasting images of fires in the nearby area.
"The death toll of the missile strike has risen to 15 pro-regime fighters -- eight from Iran's Revolutionary Guards and others not of Syrian nationality," Observatory head Rami Abdel Rahman said.
The monitor previously reported nine pro-regime combatants had died in the raid, without specifying their nationality.
SANA quoted a medical source saying that two civilians had died on a highway linking Damascus with the southern city of Deraa as a result of an explosion linked to "the Israeli aggression".
Late Tuesday, the Israeli-occupied section of the Golan Heights was placed on high alert due to "irregular activity by Iranian forces" across the demarcation line in Syria.
It is not the first time that Kisweh has been targeted. In December, Israel reportedly bombed military positions in the area south of Damascus, including a weapons depot.
Since the start of Syria's civil war in 2011, Israel has repeatedly targeted positions of the Syrian army and the Lebanese Hezbollah movement backing it inside the country.
On April 29, missile strikes -- "probably Israeli" -- fired on regime military positions killed at least 26 mostly Iranian fighters, according to the Observatory.
On April 9, missiles targeted the T-4 air base in the central province of Homs, killing up to 14 fighters, including seven Iranians, two days after an alleged chemical attack carried out by the Syrian regime.
Damascus accused Israel of carrying out the strike.
Israel and Syria are still officially in a state of war, though the armistice line on the sector of the Golan Heights which the Jewish state seized from its Arab neighbour in 1967 was largely quiet for decades until the Syrian civil war broke out in 2011.
In an interview late last month, Israeli Defence Minister Avigdor Lieberman vowed to strike at any attempt by Iran to establish a "military foothold" in Syria.