LONDON (Reuters) -Britain on Wednesday moved to loosen the grip of Apple ( AAPL ) and Google in smartphones by designating them as having "strategic market status", giving it the power to demand specific changes to boost competition.

The Competition and Markets Authority said Apple ( AAPL ) and Google's mobile platforms were used by businesses right across the economy, but the platforms' rules may be "limiting innovation and competition".

It said it was joining the United States, the European Union, Japan and others in taking action to support businesses and consumers dependent on mobile platforms.

Nearly all smartphones in Britain run on either Apple's ( AAPL ) iOS or Google's Android operating systems, and their respective app stores and browsers have exclusive or leading positions on their platforms.

The CMA said its decision was not a finding of wrongdoing and did not introduce any immediate requirements, but it would now consider "proportionate, targeted interventions" to ensure the platforms were open to effective competition.

Google, which received the first ever SMS designation earlier this month for its search operations, said the second was "disappointing, disproportionate and unwarranted".

"The CMA's next steps will be crucial if the UK's digital markets regime is to meet its promise of being pro-growth and pro-innovation," Google's senior competition director Oliver Bethell said in a blog post.

Apple ( AAPL ) said it "worked tirelessly" to create the best products, services and user experience.

"The UK's adoption of EU-style rules would undermine that, leaving users with weaker privacy and security, delayed access to new features, and a fragmented, less seamless experience," Apple ( AAPL ) said.

"We've seen the impact of regulation on Apple ( AAPL ) users in the EU, and we urge the UK not to follow the same path."