Islamic State was selling oil and gas to the Syrian regime and to Turkey, while the militants were ruling over large areas in Syria and Iraq over the past three years, a senior ISIS commander said in an interview with the Kurdistan 24 news outlet on Sunday.

“Oil and gas obtained by the Islamic State was sold to Turkey and the Syrian regime,” Razeek Radeek Maksimo, an Azerbaijani national and formerly senior ISIS commander, told Kurdistan 24 from a prison in Rojava where he is held by Syrian Kurdish authorities.

“[Oil] was sold to Turkey through the Free Syrian Army (FSA),” Maksimo told Kurdistan 24.

The detainee has claimed that he was only responsible for a number of checkpoints in territories run by ISIS. According to information that Kurdistan 24 has obtained from the Kurdish authorities in northern Syria, Maksimo was a senior commander at one of the strategic institutions of ISIS in Raqqa, northern Syria, the self-proclaimed capital of the militants who were expelled from it in October last year.