Istanbul, Turkey (CNN) -- A collection of some of Syria's most powerful rebel brigades have rejected a Western-backed opposition group that announced the creation of an interim government in exile this month. The 13 rebel groups, led by the al Qaeda-linked al-Nusra Front, also called on supporters of the Syrian opposition to embrace Sharia law "and make it the sole source of legislation." The move appeared to sideline the flagging National Syrian Coalition, which recently announced the formation of an interim government in exile led by Ahmad Tomeh, a dentist and dissident from the Syrian city of Deir Ezzor. In a statement released late Tuesday, the 13 rebel groups declared that "the coalition and the putative government headed by Ahmad Tomeh does not represent or recognize us."
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Syrian rebel brigades oppose Western-backed group that announced government in exile
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Thirteen rebel groups call on supporters of the Syrian opposition to embrace Sharia
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Moderate opposition groups appear to have suffered a series of setbacks this month
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Secular Syrian activists have been warning of the rise of Islamist groups
The activist asked not to be named, for fear of reprisal from @placeholder groups.