Mobile privacy safeguards should also extend to third-party application developers, two lawmakers said after reviewing the practices of four major U.S. wireless carriers.

Representatives Edward Markey and Joe Barton, co-chairs of the House Bi-Partisan Privacy Caucus, released on Thursday letters they received from Verizon Wireless, AT&T Inc, Sprint Nextel Corp and T-Mobile in response to their inquiries last month about the collection, use and storage of location data.

The letters showed the wireless carriers generally asked customers before accessing their location data.

But developers of popular mobile phone applications were less than forthcoming about their tracking.

Third-party developers can access the location of customers any time they want, Barton said. They shouldn't have free reign over your location data and personally identifiable information.

Markey echoed this sentiment, saying consumer privacy protections must apply across the entire wireless ecosystem -- from wireless carriers, to mobile handset makers, to application developers.

Markey and Barton grew concerned about location tracking after media reports found that Deutsche Telekom AG tracked the exact coordinates of a German politician using its service over a six-month period.

More recently Apple Inc has been caught in a firestorm that has broken out over whether it is monitoring the whereabouts of its customers, promising to adjust the mobile software to store less location data.

Google Inc, a fierce competitor of Apple in mobile computing, has also faced sharp criticism over reports that Android-based phones track the locations of users.

Senate Commerce Committee Chairman Jay Rockefeller will hold a hearing in May on consumer protection and privacy in the mobile marketplace. Senator Al Franken said on Thursday both Google and Apple would attend his May 10 hearing, the first by the new Senate judiciary subcommittee on privacy, technology and the law.

It is unclear if this legislative scrutiny will lead to strict new privacy laws that will include app developers.

You'll see Congress give it a lot of attention, but it's still going to be difficult to get comprehensive privacy legislation out of this Congress, Medley Global Advisors analyst Jeffrey Silva said.

(Reporting by Jasmin Melvin; editing by Andre Grenon)

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