A member of the Syrian Observatory for Human Rights told CNN today the US blacklisted the al-Nusra Front less out of security concerns -- the US labeled the group a proxy for Al Qaeda in Iraq -- more because they disagreed about Syria's future.
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"The United States decided to single out the Nusra Front because of their recent rejection to the political opposition front and [because] they have a different approach to post-Assad's Syria," the Observatory's Rami Abdelrahman told CNN.
Foreign Policy's Aaron Zelin earlier said there is "not much open-source evidence" of the group's ties to Al Qaeda in Iraq, but "classified material may offer proof -- and there is certainly circumstantial evidence that Jabhat al-Nusra operates as a branch of the ISI," referring to the Islamic State of Iraq.
The UK-based group has closely monitored both rebel and regime-led violence in Syria, where months of fighting between opposition forces and forces loyal to Syrian President Bashar al-Assad has taken tens of thousands of lives.
The sanctions come a day ahead of an international crisis meeting on Syria, set to be held in Morocco, said CNN.
Note: The original version of this piece incorrectly stated that Zelin was referring to Pakistan's Inter-Services Intelligence Unit with the acronym ISI. It has been changed to reflect the correction.