Underscoring their violent ongoing fight against other rebel factions in northern Syria, the Islamic State of Iraq and Syria (ISIS) carried out eight public crucifixions of captured rivals over the weekend in the Aleppo Province.

Rebel mouthpiece the Syrian Observatory for Human Rights said the eight were crucified on Saturday because they were “considered too moderate.” ISIS accused them of being Sahwa fighters, their catch-all term for US-backed rebels.

Exactly what faction the crucified rebels were from is unclear, as ISIS is fighting with multiple other rebel factions, most notably the Islamic Front and the Free Syrian Army (FSA) in the region.

ISIS has carried out crucifixions on occasion in the past, but this appears to be the single largest such incident. Coinciding with today’s declaration of their territory as The Islamic State, ISIS is pushing to establish itself as the unquestioned leader of the Syria rebellion, and indeed the unquestioned leader of international jihad in general.