North Korea has declared itself a "nuclear power" in its recently revised constitution.
A source in Tokyo has confirmed that the amended constitution, which can be read on a North Korean state-run website called "Naenara", clearly states that the country is a nuclear-armed state.
The statement wasn't included in 2010 when the last revision was made.
Experts say the move is likely to have been intended to win international recognition, and to be used as a diplomatic tool when needed.
In response, the U.S. State Department says it will not accept North Korea as a nuclear state and reiterated that the North should abide by the terms it agreed to in 2005 to abandon all of its nuclear weapons programs.