Chechen rebels called on Tuesday for prominent separatist leader Akhmed Zakayev to be killed, saying he had abandoned Islam by recognizing the legitimacy of the restive region's Kremlin-backed government.
Zakayev, who lives in London, represents the moderate wing of the separatist movement and has clashed with radical Islamist insurgents in Russia's southern republic of Chechnya.
Islamist rebel website www.kavkazcenter.com said Zakayav had recognized the authority of Ramzan Kadyrov, the Kremlin-backed leader of the region.
"Public remarks show that he (Zakayev) has fallen away from Islam," the website said, adding that Doku Umarov, Chechnya's most wanted separatist leader, was behind the order.
"The court has ruled that the killing of this apostate is a duty for Muslims." It did not say what court had issued the ruling.
Zakayev, 50, fought Russia as a senior rebel commander in two wars with Moscow in 1994-2000. After Russia regained control of the province, he fled to Europe and acted as an official rebel envoy until 2007.
Russia has tried to extradite Zakayev for 13 alleged crimes including kidnapping and murder, but a British court rejected the request in 2003, causing a diplomatic row.
Kadyrov said last month that he would welcome Zakayev's return and possibly offer him a job in the regional culture ministry. But there were no indications Russia was ready to drop charges against him.
Kadyrov faces strong criticism from human rights bodies after kidnappings and killings of human rights and charity activists in Chechnya. He denies any link to the killings.