Several powerful Islamist rebel groups have rejected the authority of the main opposition Syrian National Coalition, calling for an Islamic leadership. Thirteen groups signed a statement late Tuesday calling for the opposition to be organized under an Islamic framework and led only by groups fighting within Syria, saying, “all groups formed abroad without having returned to the country do not represent them.”

Three of the groups have been considered part of the Western-backed Supreme Military Council that leads the Free Syrian Army. The move may threaten international efforts to organize the increasingly divided Syrian opposition and may jeopardize funding as the West has sought to funnel assistance to moderate factions. Meanwhile, a team of U.N. chemical weapons inspectors has returned to Damascus in order to investigate up to 14 instances of alleged chemical weapons use. The team will again be led by Ake Sellstrom, who said they hoped to release a final report “possibly by the end of October.”