The government said Friday that the arms-laden vessel that sank in December in the East China Sea after a gunbattle with Japanese patrol boats is a North Korean spy ship.

Tokyo is now investigating why the boat was dispatched to Japanese waters and hopes to receive answers on this issue during normalization talks with Pyongyang, key ministers said.

“Now we can label (the boat) a spy ship,” from the results of investigations carried out both before and after the boat was raised, Chief Cabinet Secretary Yasuo Fukuda told reporters.

Chikage Ogi, who heads the Japan Coast Guard as minister of land, infrastructure and transport, told a separate news conference, “Material evidence substantiated that it is a spy ship from North Korea.”

Ogi was referring to the crew’s belongings and the boat’s design.

Ogi said Japan’s investigative team discovered several pins bearing the image of former North Korean leader Kim Il Sung, along with several packs of North Korean cigarettes and confectionery.

The stern of the boat also features a pair of doors that open outward — a characteristic of North Korean spy boats, Ogi said.

“But we have little evidence (to determine) the purpose” of the boat’s activities, said Fukuda, the government’s top spokesman.

Prime Minister Junichiro Koizumi told reporters at his office, “We need further research (on the boat).”

The boat sank in waters west of Amami-Oshima Island in December after exchanging fire with coast guard patrol vessels.

While there were several explosions on the vessel before it sank, the exact cause of the sinking has yet to be determined, according to the government.

Three coast guard officers were wounded in the shootout; all crew members aboard the North Korean boat are presumed dead.

Japan will step up its investigation of the spy ship’s activities during negotiations leading up to normalization talks slated to start later this month, Fukuda said.

Later Friday, the Japan Coast Guard released photos and detailed information related to the powerful weapons on board the ship.

The coast guard, which salvaged the 130-meter ship on Sept. 11, has thus far retrieved the remains of at least seven crew members.

It has also retrieved a 14.5mm heavy machinegun that has a firing range of 1,000 meters and looks like a Russian ZPU-2 anti-air heavy machinegun, two anti-air missile launchers with a range of 5,000 meters, two shoulder-held rocket launchers, four 5.45mm-caliber automatic rifles, an 82mm antitank recoilless gun, and six hand grenades.

One of the rocket launchers, which looks like a Russian RPG7 rocket launcher, features a red star — the national symbol of North Korea — and Korean characters denoting it is a 1968-type No. 7 Firing Tube.

The automatic rifles, which look like Russian-made AKS-74 rifles, feature a carved seal of a North Korean red star on their surface, the coast guard said.

The ship was disguised as a Chinese fishing vessel, bearing the name of a Chinese port on its stern.

But a wooden board bearing a fake Japanese fishery registration number was also recovered, indicating that the crew members were ready to try and disguise the vessel as a Japanese ship.

The coast guard also salvaged another wooden board bearing Korean characters that read, “Oh The Party, this child will be your loyal retainer for good.”

It also said new patrol ships featuring 40mm machineguns should be introduced.

During the Sept. 17 summit with Kim Jong Il in Pyongyang, Koizumi protested Pyongyang’s use of spy boats, claiming that the North had used the boats in a series of abductions of Japanese nationals.

Foreign Minister Yoriko Kawaguchi echoed these comments.

The North Korean leader “admitted part of the (North Korean) military operated spy ships and such cases will not happen again,” she said.