BERLIN (AP) — The head of a European Union military task force in the Mediterranean Sea says Libya's coastal cities are generating up to 325 million euros ($346 million) in revenue each year from people smuggling.

Rear Adm. Enrico Credendino cites the figure in a confidential report assessing the work of Operation Sophia, a naval mission intended to stop the flow of migrants to Europe.

The report, issued to EU member nations Wednesday and obtained by The Associated Press, provides no details on how the figure was calculated. EU officials didn't immediately respond to questions Thursday.

Credendino describes the smuggling as a "major source of income among locals in Libyan coastal cities."

He also says Islamic extremist groups are "financially exploiting" smuggling routes that lead through Africa's Sahel region into Libya.