The UN Secretary-General Antonio Guterres is closely watching the alarming military escalation in Syria. In a UN announcement, he stressed that all concerned in Syria and in the region must abide by international law. Russia also has called on all sides to exercise restraint and work for an immediate de-escalation of violence. Russian President Vladimir Putin and Israeli Prime Minister Benjamin Netanyahu, discussed the situation in a phone call on Saturday. And the Pentagon on Sunday said the US fully supports Israel's right to defend itself and denounced Iran as a threat to regional security.