TOKYO (AFP) - Four fisherman died and another four were missing Friday following a boat fire in waters near islands at the centre of a dispute between Tokyo and Beijing, Japan's coastguard said.Five of the nine-member crew from the 29-ton, South Korea-flagged 3005 Hwang Gum longliner were pulled from rough waters in the East China Sea, but four later died, Japan's coastguard said, citing fishermen's reports to South Korean authorities."We have dispatched two vessels that arrived at the scene at 1:30 pm (0430 GMT) and 2:15 pm (0515 GMT). Our mission has focused on finding the missing people," a coastguard spokesman said. A plane was also scrambled to join the hunt for the fishermen, he added.The fire was first reported by the crew of another South Korean vessel in waters some 100 nautical miles north of Uotsuri, the largest island in the Tokyo-controlled Senkaku chain, claimed by Beijing as the Diaoyus.Seven crewmen from the stricken ship were South Korean and two were Chinese, Japan's coastguard said, adding that they had donned lifejackets and jumped into the water when the fire caused the boat to start sinking. "We don't know yet the nationality of the dead and missing," the coastguard spokesman said.The search for the men was being hampered by heavy seas, with strong winds and waves up to three metres (10 feet) high, the spokesman added.The maritime dispute between Tokyo and Beijing, which has simmered for years, escalated last year when the Japanese government nationalised some of the islands, triggering anger and demonstrations in China.Observers said the protests had some backing from communist authorities in Beijing, who use nationalism to bolster their claims to legitimacy.Tokyo's defence ministry has said F-15s were sent airborne to head off Chinese state-owned - but not military - planes four times in December, including one occasion when Japanese airspace was breached.They were also mobilised in January, it said.Tokyo is embroiled in a separate row with Seoul over a different set of islets, with tensions flaring last summer after South Korean President Lee Myung-Bak paid a sudden visit to the disputed territory.