So Chung On, director of the International Affairs Bureau of the General Association of Korean Residents in Japan, said Pyongyang had no problem with inspections of its ships within a country's territorial waters.

"But if the US tries to inspect our country's ship in the public sea, that will cause a serious matter," he said in English to reporters.

"If something happens illegally toward North Korea by the US, that means the US withdraws the armistice treaty, that means the start of war," he said, referring to the armistice following the 1950-53 Korean War.

So's comments followed last month's UN resolution calling for inspection of cargo entering and leaving North Korea. The resolution was adopted in response to Pyongyang's October 9 nuclear test.

So also denounced Tokyo's sanctions against Pyongyang, saying they have repercussions on North Koreans living in Japan.

Japan stepped up its sanctions after the North's nuclear test, banning all of the country's vessels from Japanese ports, all imports from North Korea and severely limiting travel from the country.

So's association functions like an embassy, because Japan and North Korea have no diplomatic ties.