German authorities have arrested a man accused of supporting the Islamic State group by offering it his services as a translator and proofreader.

Federal prosecutors said the 18-year-old German national, identified only as Mikail S. in line with German privacy rules, was arrested in the west of the country on Thursday.

He is accused of supporting a foreign terrorist organization. Prosecutors said in a statement Friday that he's suspected of offering IS his services to translate texts in English, Turkish and German and to check those texts for linguistic errors.

They say he's believed to have proofread nine texts between the beginning of June and early July, some of which were then posted on the internet.