Rebels seized control of Syria's border crossings with Iraq on the bloodiest day of the uprising against President Bashar al-Assad, as China and Russia dismayed the West by blocking UN action against his regime. The rebel offensive on Syria's eastern border on Thursday came as the army focused its resources on Damascus, resorting to tank fire in the capital for the first time in its efforts to root out rebel fighters a day after a bomb blast killed three of Assad's top aides. [Link]