US anti-trust regulators plan to investigate whether Apple is unfairly restricting rivals such as Google from carrying ads on the iPhone, iPad and iPod, the Financial Times said.
The regulators have already started scanning Apple's actions, the paper said, citing people familiar with the move.
But it is not yet clear whether the Federal Trade Commission or the Department of Justice would take up an investigation, the Times said.
Apple could not immediately be reached for comment.
On Wednesday, Google had said recent changes to Apple's developers agreement would effectively cripple Google's advertising tools for the iPhone, creating "artificial" barriers to competition.
Apple changed the language of the agreement on Monday, which now appears to prohibit certain third-party ad agencies from collecting critical usage data from iPhone applications.
Google said the new language would effectively prevent the Internet search and advertising giant from placing ads inside iPhone applications.
Omar Hamoui, founder of AdMob, a mobile advertising startup which Google bought last year, said Apple's new terms of service for application developers would bar the use of AdMob or Google advertising solutions on iPhones.
Apple’s own advertising platform, iAd, allows software developers or ad agencies to embed ads directly into applications being offered for the iPhone, the iPod Touch and the iPad.
Apple's new terms would appear to prohibit Google — and also Microsoft — from collecting user location data from applications running on the iPhone.
{{/usCountry}}Apple's new terms would appear to prohibit Google — and also Microsoft — from collecting user location data from applications running on the iPhone.
{{/usCountry}}Location data is considered extremely important by mobile advertisers because it allows them to deliver ads that are more relevant to users.
Apple's terms state that only an "independent advertising service provider whose primary business is serving mobile ads" can collect such data — evidently ruling out Google and Microsoft, which are both developers of mobile phone operating systems.