Updated

The leader of al-Qaida has called on Syrian militant groups to determine who killed his representative in the country, a man many fighters believe died at the hands of a rival militia.

In a recorded message posted on militant websites late Friday, Ayman al-Zawahri endorsed a previous call for Islamic arbitration by the al-Qaida-linked Nusra Front over the death of Abu Khaled al-Suri, who it and its allies say was killed by the Islamic State of Iraq and the Levant.

Al-Zawahri called al-Suri's killing "sedition" and said that "all Muslims should confront it and form a general opinion against it and against anyone who does not accept the Shariah arbitration." The Islamic State has not responded to the arbitration call.