Powerful Syrian insurgent units have rejected the authority of the opposition Syrian National Coalition, badly damaging efforts by Western-backed political exiles to forge a moderate rebel military force.
Thirteen groups have signed a statement calling for the opposition to the al-Assad regime to be reorganised under an Islamic framework and to be run only by groups fighting inside Syria.
The signatories range from hardliners such as the al Qaeda-linked Nusra Front and Ahrar al-Sham battalions to more moderate Islamist groups such as the Tawheed Brigade and Islam Brigade, the news agency Reuters reports.
"These forces feel that all groups formed abroad without having returned to the country do not represent them, and they will not recognise them," said the statement read in an online video by Abdulaziz Salameh, the political leader of the Tawheed Brigade.
"Therefore the National Coalition and its transitional government led by Ahmad Tumeh do not represent them and will not be recognised," he said.
Western powers and their Gulf Arab allies had encouraged the SNC to lead a credible force within Syria under the FSA's banner and undercut Islamist militant groups piling into the conflict.
Meanwhile, United Nations weapons inspectors have returned to Syria to continue investigating the sarin attack that killed hundreds of people on the outskirts of Damascus on 21 August.