North Korea has warned that it would regard any sanctions imposed on it by Japan as a declaration of war.

In a statement carried by the North’s official KCNA News Agency, a foreign ministry spokesman said Wednesday that “if sanctions are applied against the North, Pyongyang will regard it as a declaration of war and promptly react to the action by an effective physical method.”

The spokesman also said that Pyongyang would also reconsider taking part in six-nation nuclear talks if what it called a "provocative campaign" under way in Japan against the North continues.

The spokesman said North Korea suspects recent DNA test results disclosed by Japan were "cooked up" to serve a political purpose.

The North’s statement comes as calls are growing in Japan to impose economic penalties on the North after DNA tests showed that remains provided and claimed by the North to be those of two missing Japanese abductees turned out be those of somebody else.

Earlier on Tuesday, a panel of the Diet’s Upper House adopted a non-binding resolution calling for limiting remittances to the North and banning North Korean ships from entering ports in Japan.