strongAleppo:/strong Abu Bakr, a Syrian rebel commander on the outskirts of Aleppo, is a devoted Islamist determined to overthrow President Bashar al-Assad. But the radical allies that have joined the rebels in recent months alarm even him. Let me be clear. I am an Islamist, my fighters are Islamists. But there is more than one type of Islamist, he said. These men coming fought in insurgencies like Iraq. They are too extreme, they want to blow up any symbol of the state, even schools. Seventeen months into the uprising against Assad, Syria's rebels are grateful for the support of Islamist fighters from around the region. They bring weapons, money, expertise and determination to the fight. [caption id=attachment_410075 align=alignleft width=380