Apple is being warned against trying to squeeze cash out of the newspaper industry by controlling subscriptions for iPads and iPhones.
The European Newspaper Publishers' Association (ENPA) says it is concerned by the company's plans to direct online sales through iTunes.
If that happens, the ENPA warns, a large cut of their profits would go to Apple.
However, the technology giant insists it wants to give customers choice.
Several European Newspapers claim that Apple has banned them from offering free electronic editions to their print customers.
The move sparked industry speculation that a further clampdown was imminent.
Publishers' main concern is that users will not be allowed to subscribe via newspapers' own websites.
In a statement, the ENPA said: "consumers may only have access to the newspaper of their choice via the iTunes store, where the transaction would be subject to commission."
Apple currently receives a 30% share of revenue from apps and eBooks sold this way.
Official investigation
Publishers are also worried that if Apple takes control of sales, they could lose access to subscribers' personal information.
Details such as age, sex and location are useful when selling advertising.
Apple declined to comment on the ENPA's criticism.
The company has previously denied that it plans to stop users from buying subscriptions through publishers' own websites.
However, it has introduced a rule that newspaper apps must include an option to purchase through iTunes.
Critics argue that the ease of "in app" subscription means most users will opt for Apple's preferred method.
In a related move, Belgium's economy minister has called for an official investigation into Apple's plans to sell e-newspapers.
Vincent Van Quickenborne has suggested that the company may be abusing its dominant position in the market.
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