WASHINGTON - The US Department of Defense plans to step up security for mobile devices against the "new boundary of threat," according to part of its mobile device strategy released on Friday.

The newly released strategy focuses on improving "reliable" and "secure" wireless infrastructure, mobile devices and mobile applications, said the Pentagon.

As part of the mobile device strategy, the Pentagon plans to develop a wireless security architecture that "mitigates the risks of mobile device exploitation" and enable the management of mobile devices, applications and network connections to secure the interfaces between the Pentagon networks and commercial networks.

The growing numbers of mobile devices expand the boundary of threat, and make them targets for traditional security risks as well as sophisticated new forms of attack, the Pentagon said in the documents.

Mobile device use of third-party and commercial wireless networks and short range networks like Bluetooth introduce additional vulnerabilities, said the Pentagon.

The Pentagon personnel become increasingly mobile with a wide variety of devices as well as the increasing use of social media, said Teri Takai, Pentagon's chief information officer.

Takai said the challenge is ensuring the networks can "securely support the information demands" of mobile device users, allowing them to "make informed decisions in the execution of their missions".

The scope of the Pentagon's mobile device user base is significant, with more than 250,000 commercial mobile devices and several thousand Apple and Android operating systems, said the Pentagon.