Japan dispatched diplomats Thursday to negotiate the release of three fishermen detained by Russia after a high-seas shooting that killed a fellow crew member. Tokyo said the incident could affect ties with Moscow.

A Russian patrol boat opened fire on the fishing vessel, killing one Japanese man in the latest flare up of a 60-year-old territorial dispute over a series of islands off Japan's northernmost island.

Russia seized the boat after the incident, accusing the crew of illegal fishing and taking the three survivors to Russia for further questioning.

CountryWatch: Japan | Russia

Russia's ITAR-Tass news agency, quoting officials with the Russian Prosecutor's Office, reported that the three were charged with poaching, smuggling and border violations. The crew has been refusing to give evidence to prosecutors, the agency said.

Japan's Foreign Ministry on Thursday pressed again for the immediate release of the fishermen. It protested Russia's response to the alleged poaching as too extreme and demanded that the officials responsible for the shooting be punished.

A group of Japanese diplomats was dispatched Thursday to Hokkaido to seek the release of the detained crew members and their seized boat, and to receive the dead fisherman's body, Foreign Ministry spokesman Noriyuki Shikata said. They were expected to go to nearby Russian-controlled islands for talks with Russian authorities.

"We don't think the use of force is acceptable in those circumstances," Shikata said. "If there is not good cooperation obtained from the Russian side, this could negatively affect bilateral relations."

Russian officials have said they had discovered freshly caught crabs on the fishing boat: Japan's Fishery Agency acknowledged that crab fishing in that area is illegal at this time of year under an agreement between the two nations.

Russian officials also said the boat ignored orders to stop, was maneuvering dangerously and tried to ram a Russian dinghy. They claimed the fisherman was mistakenly killed by a warning shot as he rushed to recover fishing equipment aboard the fishing boat.

Each country claims the fishing boat was in its own territorial waters at the time of the shooting.

The four disputed islands — called the Kurils in Russia and the Northern Territories by Japan — were seized by the Soviet army near the end of World War II. Tokyo has demanded their return, and the dispute has blocked a treaty formally ending wartime hostilities.

The islands are surrounded by rich fishing waters and are believed to have promising offshore oil and natural gas reserves, as well as gold and silver deposits.

Russian authorities have seized dozens of Japanese boats and injured several fishermen over the years, but this was the first shooting death of a Japanese in the region since October 1956, Coast Guard officials said.