Israel is looking into reports on Thursday, May 30 that Syria had received the first shipment of the advanced Russian air defense system S-300, an Israeli official said, according to Reuters.

"I have no information beyond what has been reported, which we are looking into," the official told Reuters on condition of anonymity, after a Lebanese newspaper quoted Syrian President Bashar al-Assad as saying a shipment had arrived.

Israel, which has made veiled threats to prevent S-300 missiles from becoming operational in Syria, has lobbied the Russians against the sale and said on Tuesday that shipments had not yet been made. Israel's airspace would be within range of the system if it is deployed in Syria, a northern neighbor.