Six top tech companies have signed on to privacy guidelines for mobile applications that will provide consumers with more information about how their personal information is being used, California Attorney General Kamala Harris said Wednesday.

Apple, Google, Amazon, Microsoft, Hewlett-Packard and Research In Motion agreed to allow users to review an app's privacy policy before they download the app, Harris said.

"Your personal privacy should not be the cost of using mobile apps, but all too often it is," she said.

The agreement brings the companies' mobile platforms into line with California's 2004 Online Privacy Protection Act, the nation's first state law to require websites and online services that collect personal information to post a privacy policy.

None of the companies could be immediately reached for comment on the privacy rules.

Harris said that the majority of apps currently on the market don't tell users how their personal data is collected, used and shared. Mobile applications often have access to a wealth of information, including a user's location, contacts, identity, messages and photos.

App developers can be prosecuted under California competition and false advertising laws if they don't comply with the regulations.

The accord was signed one week after the Federal Trade Commission (FTC) said parents needed more information about how apps were using their children's private data.

"Parents generally cannot determine, before downloading an app, whether the app poses risks related to the collection, use, and sharing of their children's personal information," the FTC said.

The agency recommended that parents be provided information about how data is collected, used and shared before downloading an app for their children.

The FTC report came the same week that Apple was questioned about its privacy practices after iOS social networking app Path admitted it had improperly stored users' personal information on its servers.