North Korea is calling the resumed construction of its two nuclear reactors a "self-defense measure."

A North Korean website "Uriminzokkiri" on Thursday also said the North's withdrawal from the Nuclear Non-Proliferation Treaty and nuclear deterrent are to protect against hostile US policy to isolate and suppress the North.

The comments are raising concern that construction of the 50 and 200-megawatt plants may have reach an advanced stage.

In December 2002, the North announced the restart of its frozen nuclear development and immediate resumption of the operation and construction of nuclear facilities.