The U.S. Joint Forces Command says in a report that South Korea and Japan are highly capable of producing nuclear devices, should they decide to do so.

In its Joint Operating Environment (JOE) 2010 released last month, the JFC said "several friends or allies of the United States, such as Japan and South Korea, are highly advanced technological states and could quickly build nuclear devices if they chose to do so."

The 2008 report identified North Korea as a "nuclear power," which had raised controversy.

This year, the North is described as "pursuing nuclear weapons technology and the means to deliver them."