Russian federal agents in Bashkortostan say they’ve arrested a man suspected of fighting with a Russian-speaking group tied to the terrorist organization al-Qaeda since at least 2014, the newspaper Kommersant reports. The Federal Security Service (FSB) has not named the individual, but a spokesperson says the suspect was detained earlier this month by guards while crossing the Turkish-Syrian border, before being returned to Russia.

The FSB says the man in custody has confessed to fighting with jihadists and is now cooperating with its investigation.