The ship had pretty high strike capabilities and was heavily armed

Prime Minister Junichiro Koizumi

Japan on Monday raised the possibility that the crew had scuttled the ship.

Japanese officials say the pictures released on Monday show the crew of the foreign boat using shoulder-held rocket launchers.

Japanese Prime Minister Junichiro Koizumi said that his forces fired in self-defence against what government authorities called a North Korean spy ship.

"The ship had pretty high strike capabilities and was heavily armed," Mr Koizumi said.

Japanese coast guards reported that two bodies had been found, with one wearing a lifejacket with Korean lettering.

North Korea has not commented on the incident.

First attack

BBC correspondents say this is the first time in almost half a century that the Japanese coast guard has directly attacked a foreign ship in waters claimed by Japan.

The boat was outside territorial waters, but within the 200-nautical mile exclusive economic zone, where Japan claims the right to protect its fishing and mineral resources.

Japanese pictures show bullet holes

Mr Koizumi commended the coast guard for the operation, but said that the incident showed the need to reform Japan's self-defence guidelines.

He said that the country's pacifist constitution meant the coast guard could not act as soon as the situation arose and could not co-ordinate with other armed forces.

The incident began on Friday when the vessel, suspected of being a North Korean spy or smugglers' ship, was first spotted inside an area where Japan has exclusive fishing rights to the south of the country.

Japanese patrol boats opened fire as the unidentified vessel fled in the direction of China, having failed to heed warning shots and an order to stop.

Regional tensions

China has expressed concern about the incident, which happened about 400 kilometres (248 miles) north-west of the Japanese island of Amami Oshima.

BBC correspondents say Japan has become sensitive about intrusions into its exclusive economic zone since an incident in March 1999, when Japanese warplanes and destroyers opened fire for the first time since World War II on two suspected North Korean spy boats.

Last year, Japan and China were involved in a row after a series of incidents in which alleged Chinese spy vessels entered Japan's waters without notice.

Since then, the Japanese coastguard has deployed high-speed boats carrying 20mm machine guns and sophisticated search-and-surveillance technology, including night vision.