Japan's government appears split over what role it legally can take in any inspections of North Korean ships in international waters. Debate is under way on the subject in wake of the United Nations Security Council resolution on North Korea.
Japan's defense agency and the foreign ministry are at odds on how to respond to the U.N. Security Council resolution punishing North Korea for its October 9 nuclear test.
The resolution calls for U.N. members to cooperate on inspecting cargo to and from North Korea, to block shipments of banned weapons material and luxury goods. It says such actions should be in accordance with national and international law.
It is that disparity between domestic and international law that is causing confusion in Tokyo.
Defense Agency Director General Fumio Kyuma says that under Japanese law the current situation is not an emergency. That means Japan's forces will not even be able to provide rear support for any forced inspections of North Korean vessels.
Kyuma says the level of tension, at present, does not equal a condition that could lead to an armed attack on Japan, thus the criteria for Tokyo to conduct such interdictions under its pacifist constitution is not met.
Japan's Foreign Ministry officials take a different view, suggesting that because North Korea is a U.N. member it can not object to enforcement of the resolution.
Japanese media have reported that the government wants its military planes and ships to support U.S.-led inspections of North Korean ships. But the reports say Japan's forces would not forcibly inspect any North Korean ship - leaving that to other countries.
Japan has been a proponent of the U.S.-led Proliferation Security Initiative. About 75 countries take part in the program, which uses ship inspections to deter North Korea and other countries from trading in missile and nuclear technology.
How the rules for P.S.I. will be adapted for the U.N. resolution is among the items U.S. Secretary of State Condoleezza Rice discussed this week with officials in Tokyo and Seoul.
Both South Korea and China have expressed reservations about forcible cargo inspections, which they believe might escalate the crisis.
Media reports Friday say the United States was tracking a suspicious merchant vessel that had left a port southwest of Pyongyang. But U.S. officials are playing down suggestions that an interception of the vessel on the high seas is imminent.