According to the activists, the festivities broke out between the Shamiya Front and Jaish al-Islam
...Liwa al-Islam (Brigade of Islam) was established by Zahran Alloush, the son of Saudi-based religious scholar Abdullah Mohammed Alloush, after Syrian authorities released him from prison in mid-2011 where he had been serving time for his Salafist activism. The group claimed responsibility for carrying out the July 2012 Damascus bombing that killed Defense Minister Dawoud Rajiha, Deputy Defense Minister Asef Shawkat, and Assistant Vice President Hassan Turkmani. It was a driving force behind actions in the Damascus region. It cooperated and conducted joint operations with al-Nusra. In Sptember 2013 Saudi Arabia engineered Liwa al-Islam's merger with fifty other more or less Salafist groups as a counterweight to al-Nusra, which the Learned Elders of Islam considered was growing too powereful...No casualties have been reported.
The reason for the festivities are unknown; however, these two groups were involved in a recent tiff after the Shamiya Front attacked a merchant from the East Ghouta region.
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