Islamic State has sanctioned the harvesting of human organs in a previously undisclosed ruling by the group's Islamic scholars, raising concerns that the violent extremist group may be trafficking in body parts.

The ruling, contained in a Jan. 31, 2015, document reviewed by Reuters, says taking organs from a living captive to save a Muslim's life, even if it is fatal for the captive, is permissible.

Reuters couldn't independently confirm the authenticity of the document. U.S. officials say it was among a trove of data and other information obtained by U.S. special forces in a raid in eastern Syria in May.