The Pentagon and Department of Homeland Security unveiled an agreement on Wednesday designed to boost cooperation in defending military and private computer networks from growing cyber threats.

"Effective cybersecurity means protecting critical networks against a wide range of state and non-state actors that do not adhere to physical borders," Homeland Security Secretary Janet Napolitano and Pentagon chief Robert Gates said.

Napolitano and Gates said the agreement, which takes effect immediately, "will align and enhance America's capabilities to protect against threats to our critical civilian and military computer systems and networks."

"We are building a new framework between our Departments to enhance operational coordination and joint program planning," they said in a joint statement.

Cybersecurity was the scene of fierce turf battles under the previous administration between Homeland Security and the Pentagon's super-secret electronic surveillance National Security Agency (NSA).

A top Homeland Security cybersecurity official quit in March of last year, complaining that the department had been sidelined and US cyber protection efforts were being dominated by the NSA.

President Barack Obama has made cybersecurity a top priority since taking office and he named Howard Schmidt, a former Microsoft chief security adviser, as overall cybersecurity coordinator in December of last year.

Napolitano and Gates said the agreement forged between their departments "formalizes processes in which we work together to protect our nation's cyber networks and critical infrastructure, and increases the clarity and focus of our respective roles and responsibilities."

Under the agreement, Pentagon cyber analysts will be "embedded" within the Department of Homeland Security and a senior Homeland Security official and support team will be detached to the NSA.

"The agreement will ensure both agencies' priorities and requests for support are clearly communicated and met," Napolitano and Gates said.