A shell explodes in the town of Yabroud, near the Syrian capital Damascus, purportedly on Friday.<br /> <br />Reuters cannot independently verify the authenticity of this clip which was posted on a social media website.<br /> <br />Another clip shows the aftermath of air strikes in Douma, just outside Damascus.<br /> <br />As the violence in Syria intensifies, Israeli Prime Minister Benjamin Netanyahu said Israel was preparing for every scenario - including the possibility that advanced weapons supplied by Russia to Syria ending up in the wrong hands.<br /> <br />Netanyahu said Israel was closely following the developments in Syria at a particularly sensitive period for the Middle East.<br /> <br />He said his government was acting in a "responsible, determined and measured' manner to ensure Israel's security and prevent weapons leaks to 'Hezbollah and terror organisations'.<br /> <br />Israel has neither confirmed nor denied reports that it attacked Iranian supplied missiles stored near Damascus earlier this month that
