A North Korean fishing boat, apparently on it's way to land agents or drugs in southern Japan, was intercepted by Japanese coast guard ships. The Japanese fired warning shots and ordered the North Korean ship to stop and be boarded. The North Korean ship, which had an extensive array of electronic equipment visible, turned and steamed for Chinese waters, and eventually returned fire with automatic weapons and anti-tank rockets. Three Japanese sailors were injured, and several North Koreans were seen to go down. The four pursuing Japanese ships increased fire with their machine-guns. But the North Korean crew was seen to set off explosives and the ship quickly went down with at least fifteen men. The North Korean ship had been spotted on December 23rd, soon after it entered the 200 mile Japanese economic zone and patrol aircraft, coastguard and navy ships were sent to check it out. Recently, more North Korean drugs have been seized in Japan, partly as a result of a crackdown on pro-North Korean organizations that have long been suspected of using illegal means to raise money for North Korea. Over the years, Japan had compiled a lot of data on how the North Koreans landed agents and drugs in Japan and have increased their surveillance along their coasts to spot these missions. North Korea has said nothing about this incident, although China has protested the shooting so near it's territorial waters.