A screw closure (1) and a security ring (2) for closing an opening of a container, the screw closure (1) being connected to the security ring (2) by way of breakable bridge elements (4), the screw closure having an internal thread (6) for screwing onto an external thread on the opening of the container. The security ring (2) includes latching means which are intended to engage behind a bead on the opening of the container such that, when the screw closure (1) is unscrewed for the first time, the bridging elements (4) break and the screw closure (1) and the security ring (2) are separated from one another. A security seal (13) is provided on the screw closure (1) and the security ring (2) and is damaged when unscrewing takes place for the first time. The security seal can be attached to the screw closure and security ring in a separate operation from the filling and closing of the container.