Oil, naturally, is a big source of revenue. ISIS controls of all of Syria's eastern oil fields, making it the premier energy supplier for the country and a racketeer for fuel. The Bab al-Salameh crossing, which is now ISIS's only means of entry into northern Syria, is responsible for feeding the entire caliphate, from Aleppo to Fallujah. "So imagine how many trucks are crossing every day," Abu Khaled said.
Yet Bab al-Salameh is controlled on the Syrian side by the non-ISIS rebels, and of course on the Turkish side by the government in Ankara. Why can't either simply shut down the crossing and deprive ISIS of its revenue stream?
"Because there is no choice. ISIS has the diesel, the oil. Last time, a little bit before Ramadan, the rebels closed ISIS's crossing." ISIS responded by turning off the tap. "The price of oil in Syria went up. The bakeries stopped because there was no diesel. The cars, the hospitals, everything shut down."