The Islamic State (IS) group's loss of at least three large Iraqi oil fields is depriving the Sunni extremist group of a crucial source of income.

The German daily Sueddeutsche Zeitung reported on April 9 that a large Iraqi counteroffensive the past several weeks had led to Baghdad retaking three of the four large oil fields held by IS fighters.

Citing the BND, Germany's foreign intelligence service, the Munich paper said IS forces have only 5 percent of the oil extraction capabilities they previously had.

The report said the IS group lost control of the Himrin and Ajil oil fields ahead of a counteroffensive by Iraqi forces.

IS still holds the northern Qayara oil field, which the BND says has a capacity of 2,000 barrels per day.

The daily said the IS "can hardly sell oil anymore," cutting off a major income source for the group.

Based on reporting by AFP and spiegel.de