A Tajik man who joined ISIS said many foreigners who enlisted in its self-declared caliphate in Iraq and Syria were jailed or killed for trying to leave.
The 28-year-old, who once drove a taxi in Moscow, said he handed himself over to the Syrian Democratic Forces (SDF), a US-backed group, from ISIS's last holdout of Baghouz in eastern Syria last month after years of trying to escape.
SDF officials monitored and recorded a Reuters interview with the man, Abdul Ahad Rustam Nazarov, at an SDF centre in Rmeilan in Syria. Reuters could not verify his account.
Tajikistan has offered amnesty to those who quit ISIS and return home, provided they've committed no other crimes.
Nazarov says he never fought for ISIS. Parts of his account about his life were inconsistent, although other parts matched what others have said about ISIS, including its strict judicial system and its eventual defeat.
"I was jailed three times for trying to leave," Nazarov said. "I wanted to come and see Islamic State for myself ... and to help those being oppressed by the Syrian government.
"But I didn't want to make a pledge of allegiance to the caliphate."
Nazarov said most foreign men who travelled to Syria were immediately taken to Mosul in Iraq for military training.
Some refused and were punished, he said, describing a special ISIS judicial section that dealt with those trying to flee or refusing to pledge allegiance.
"Some friends were executed ... because they were not ready to commit to ISIS," he said.
Nazarov said he tried more than once to escape to Turkey across the Syrian border. He said he made contact with authorities in Tajikistan to arrange for his own surrender. Tajik interior ministry and state security officials, speaking anonymously because they were not authorised to comment, said neither body had received requests from Nazarov.
Thousands of men from Central Asian are estimated to have travelled to Syria and Iraq to join Islamic State since 2014, when it declared its caliphate.
The Sunni Islamist group was driven from all territory it controlled in Iraq in 2017 and from its final redoubt of Baghouz in eastern Syria last month.
Some foreigners including Central Asians surrendered but most were killed, Nazarov said.
"There were experienced snipers in ISIS ranks who were from Chechnya. Most of them died in battle, especially in Mosul, Baiji and Raqqa," he said.
Nazarov said ISIS militants tried to stop men surrendering to the SDF in Baghouz, locking them in cars and firing at them when they eventually fled.
The US-backed campaign to drive ISIS out of Iraq and Syria involved tough battles with hardened militants, especially in Mosul and Raqqa.
Nazarov said he once met Gulmurod Khalimov, a Tajik military commander who joined ISIS, in an internet cafe in Mosul frequented by militants. He belives Khalimov was killed fighting.
Nazarov said he wanted to be reunited with his pregnant wife, a Chechen now in Al Hol camp in Syria, where 60,000 people who fled Baghouz live. "My other two children starved in Baghouz," he said.