A bitter battle has broken out between Google and Apple over the burgeoning mobile advertising market that both are seeking to dominate.

Google accused its rival of trying to muscle it out of the potentially lucrative platform of the iPhone, iPad and iPod Touch.

The rivals, once close Silicon Valley friends, have fallen out over a proposed change that could hobble Google’s ability to sell and place adverts on devices running on Apple’s latest mobile operating system, which comes out this month.

Apple and Google are competing head-on in the important smartphone sector, with handsets running Google’s Android software gaining market share rapidly.

Under the terms of Apple’s latest operating system, clarified by the company on Monday, critical information for distributing and analysing adverts cannot be shared with services owned by makers of other mobile operating systems. Effectively, this cuts AdMob, Google’s newly-acquired mobile advertising service, out of the iPhone platform completely.

Omar Hamoui, the executive in charge of AdMob, attacked Apple’s new restrictions as a threat to competition. Speculation was rising last night that federal regulators could look into the issue.

Mr Hamoui also warned that the change would decrease the advertisement revenue flowing to the developers of iPhone and iPad applications, a scenario that could drive up the prices that consumers pay for the programmes.

“This change is not in the best interests of users or developers,” Mr Hamoui said. “Artificial barriers to competition hurt users and developers and, in the long run, stall technological progress. We’ll be speaking to Apple to express our concerns about the impact of these terms.”

Apple did not respond to requests for comment.

Both Google and Apple believe that mobile devices such as smartphones eventually will supplant personal computers as the main way that people surf the internet. Both companies have been involved in increasingly outspoken skirmishes against the other in recent weeks.

Google, which dominates internet advertising on the PC, paid $750 million (£515 million) to buy AdMob, partly because of AdMob’s success selling adverts on the iPhone from under the nose of Steve Jobs, Apple’s chief executive. Apple purchased the mobile ad company Quattro Wireless.

Apple has since set up own ad service, iAd, fuelling Google’s suspicion that its rival wants to monopolise the commercial messages shown on nearly 100 million iPhones, iPads and iPod Touches already sold. iAd allows software developers or ad agencies to embed adverts directly into apps, of which there are more than 200,000 available in Apple’s App Store.

Apple will sell and host the adverts and give developers 60 per cent of the revenue, while keeping the remaining 40 per cent.

iAd will debut on the iPhone and iPod Touch on July 1. Apple has said that it has already attracted iAd commitments worth more than $60 million for 2010 from AT&T, Nissan, Disney and other companies.

It was unclear whether Apple would enforce the restrictions on how the advertising data can be shared, said Noah Elkin, an analyst for eMarketer, a research firm.

“I think what we have here is two companies sparring for control of what is potentially a very big advertising market,” he said. The US mobile ad market is expected to grow from about $600 million this year to more than $1.5 billion in 2013, according to eMarketer.

If Apple’s new rules on mobile advertising data were to create a competitive barrier, it would be likely to attract the attention of antitrust regulators.

After a six-month review, the Federal Trade Commission approved Google’s purchase of AdMob largely because the agency believed that Apple’s entrance into the mobile advertisement market would foster adequate competition. In its approval of the AdMob deal, the FTC vowed to continue to monitor the mobile advert market for anti-competitive behaviour.