Syria's national security chief today became the fourth official to die after Wednesday's rebel bombing of a high-level government meeting in the heart of Damascus. As many as 30,000 Syrians may have crossed into Lebanon in the past 48 hours. In Damascus, the bloodiest fighting yet is reported, as control of strategic neighborhoods appears to pass back and forth between rebels and government forces. Elsewhere, rebels claim to have seized border posts at crossings into Iraq and Turkey, while Syrian media claims the Army has taken them back. International efforts to end Syria's civil war have reached a standstill, and tens of thousands are fleeing the country as fighting escalates from Damascus to international borders. Will the Al-Assad dynasty come to an end? Will it resort to chemical weapons? What are the potential consequences for Middle East and US relations with Russia?