Aerial photographs reportedly show that several makeshift oil refineries have popped up at Islamic State oil fields in northern Iraq.
Aerial photos seen by the Washington Post reportedly show dozens of makeshift oil refineries at fields controlled by Islamic State near Mosul.
The refineries, sometimes known as “teapot” refineries, were built to help Islamic State bolster its oil revenue as airstrikes continue to destroy the group’s energy assets.
“In a single oil field there can be hundreds of these makeshift operations,” Omar Lamrani, senior analyst at intelligence firm Stratfor, told the Washington Post.
While estimates on the size of the Islamic State’s oil operations vary, the group was believed to be earning as much as $50 million in oil revenue before coalition airstrikes began destroying energy assets.
Texas-based Stratfor told the Washington Post that Islamic State may have been earning only $20 million per month from oil revenues as of March.
Although the exact number of Iraqi fields controlled by Islamic State is unknown, the group is believed to control about 10 percent of country’s oil fields.
Airstrikes have also crippled Islamic State’s oil operations in Syria where the militant group is believed to hold at least half the fields.
French, American and Russian forces stepped up airstrikes against ISIS after the devastating attacks in Paris last year, destroying truck conveys and tankers.
Islamic State fighters have also launched attacks on oil infrastructure in Libya.
In January, storage tanks at Libya’s Es Sider and Ras Lanuf ports caught fire after a ISIS rocket attack.
At least nine guards were killed and more than 40 wounded while defending the installations, Reuters said.