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SAN FRANCISCO June 9 (Reuters) – Google Inc (NASDAQ:GOOG) said on Wednesday 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. As written, it appears to prohibit certain third-party ad agencies from collecting critical usage data from iPhone applications.

This would hamper rival ad agencies’ ability to target their ads and make it more difficult to compete with Apple’s own ad network, which is set to launch July 1.

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"This change is not in the best interests of users or developers," Omar Hamoui, founder of mobile ad company AdMob, said in a blog post. AdMob was recently purchased by Google.

Hamoui said Google will raise its concerns with Apple, which has declined to comment on the new terms of its developers agreement.

"Artificial barriers to competition hurt users and developers and, in the long run, stall technological progress," Hamoui said.

AdMob recently disclosed that roughly one-third of the ads it served in April were for devices running the iPhone platform. The iPad and the iPod touch also use the software.