Israeli raids on Syrian targets at the weekend killed at least 15 soldiers, a watchdog said Monday, as UN chief Ban Ki-moon led calls for restraint to prevent the war spilling over borders.

UN human rights investigator Carla del Ponte, meanwhile, said that rebels have used the deadly nerve agent sarin in their fight to oust Syria's regime.

"At least 15 soldiers were killed, and dozens more are missing" after the Israeli strikes near Damascus, said Rami Abdel Rahman of the Syrian Observatory for Human Rights.

"These three sites (targeted) would usually have around 150 soldiers in them, but it's not clear if they were all there at the time of the strikes."

Sunday's pre-dawn Israeli raids were the Jewish state's second such attack on Syria in 48 hours.

A senior Israeli source said the raids targeted Iranian weapons destined for the Lebanese militant group Hezbollah.

Iran and the Shiite group Hezbollah are steadfast allies of Syrian President Bashar al-Assad's regime, and arch-foes of of Israel.

The strikes came ahead of a visit by Israeli Prime Minister Benjamin Netanyahu's to China, another ally of Assad's regime.

UN leader Ban, meanwhile, warned against any escalation of a conflict that has killed more than 70,000 people in Syria since it erupted in March 2011.

"The secretary-general calls on all sides to exercise maximum calm and

restraint, and to act with a sense of responsibility to prevent an escalation of what is already a devastating and highly dangerous conflict," his spokesman Martin Nesirky said.
(AFP)