Islamic State (ISIS) group revenues have dropped by around 30 percent since last year, forcing the group to introduce a range of new taxes including a levy on repairing satellite dishes, a research group says.
"In mid-2015, the Islamic State's overall monthly revenue was around $80 million," Ludovico Carlino, senior analyst at IHS, which issues regular reports on ISIS-controlled territory, was quoted by AFP as having said.
"As of March 2016, the Islamic State's monthly revenue dropped to $56 million," Carlino added.
An IHS report also said oil production in areas controlled by ISIS jihadists had gone down to 21,000 barrels per day from 33,000 barrels per day before.
This was due largely to air strikes by the U.S.-led coalition and Russia, although IHS warned the decline was only an "interruption of production" as jihadists were able to repair infrastructure quickly.
The report said around 50 percent of IS revenues come from taxation and confiscation of businesses and property, with 43 percent coming from oil.
The remainder is made up of drug smuggling, the sale of electricity and donations, the report said.
"The Islamic State is still a force in the region but this drop in revenue is a significant figure and will increase the challenge for the group to run its territory in the long term," Carlino said, according to AFP.
IHS said that ISIS had lost about 22 percent of its territory in the past 15 months and now ruled over six million instead of nine million people.
This meant the tax base for ISIS had become smaller.
"Our research has found that the Islamic State is increasing taxes on basic services and coming up with new ways to get money from the population," Carlino said, adding, "These taxes include tolls for truck drivers, fees for anyone installing new or repairing broken satellite dishes, and 'exit fees' for anyone trying to leave a city."
Fines for not being able to answer questions correctly on the Koran have also been introduced and ISIS is also taking cash as an alternative to corporal punishment penalties, IHS said.
ISIS is known to be the richest terrorist organization in the world and has even been the target of an economic campaign which aims to expose the inner economic workings of ISIS and related groups and to stop its campaigning through social media networks.
In January, an airstrike by the international coalition led by the United States destroyed a cash storage facility used by ISIS jihadists in the Iraqi city of Mosul. The international coalition later said it was focusing on “bombing the Daesh cash”, using the Arabic name for ISIS.
Evidence shows that the focus on ISIS cash, combined with the continued bombing of oil trucks that ferry illicit oil around Syria, is hurting the jihadists', as ISIS leaders have had to cut their fighters' salaries by as much as half.
AFP contributed to this report.