DAMASCUS, Syria—Islamist rebels, including some with links to al Qaeda, are fast gaining strength in suburbs encircling the Syrian capital, despite a chemical-weapons attack two months ago on one of their strongholds. Since early September these groups have claimed responsibility for several suicide-bomb attacks against regime targets in and around Damascus. They have dramatically increased mortar and rocket attacks on regime-held residential neighborhoods within the capital and have raided nearby towns and villages inhabited by minorities, including Christians. Last week, these rebels blew up a gas pipeline feeding a power plant on the outskirts of Damascus, causing a complete blackout in the capital and most of Syria for several hours before the damage was repaired, according to government officials and residents. While riven by leadership rivalries and competing agendas, the Islamist rebels share the goal of toppling President Bashar al-Assad and establishing Islamic rule. Their strengthening around Damascus further […]