Moscow promises to deliver sophisticated anti-aircraft missile system to Syria after arms embargo dropped.
Israel warned it "will know what to do" if Russia delivers a sophisticated anti-aircraft missile system to Syria which it promised to do after expressing anger over European Union moves to arm the country's rebels.
Moscow said it was being forced to send the S-300 system to the regime to prevent Western "hotheads" from intervening in Syria's civil war.
It came after Britain and France succeeded in persuading the EU not to renew an embargo on supplying weapons to opposition forces. William Hague, the Foreign Secretary, said the deal meant Britain could begin arming the rebels from now.
The move provoked anger in Russia, which has been implacably opposed to Western efforts to unseat President Bashar al-Assad.