Al Qaeda's rise in northern Syria leaves Turkey in a dilemma

ISTANBUL (Reuters) - The rise of al Qaeda in parts of Syria's north has left Turkey facing a new security threat on its already vulnerable border and raised questions about its wholesale support for rebels battling President Bashar al-Assad.

Turkey has long championed more robust backing for Syria's fractious armed opposition, arguing it would bring a quicker end to Assad's rule and give moderate forces the authority they needed to keep more radical Islamist elements in check.