Japan's coastguard arrested the captain of a Chinese boat on suspicion of fishing in the country's exclusive economic zone on Saturday amid a festering territorial row between the two countries.
The coral fishing boat with a crew of 13 was stopped by a coastguard patrol in waters some 45 kilometres (28 miles) northeast of Miyako island in the Okinawan chain, the local branch of the Japan Coast Guard (JCG) said.
The captain was arrested on suspicion of fishing in the exclusive maritime zone without permission from Japan, the coastguard said, adding that all the crew members called themselves Chinese.
The incident occurred amid a simmering dispute over the Tokyo-administered Senkaku islands, which China also claims and calls the Diaoyus.
Miyako is located about 210 kilometres (130 miles) off the biggest Senkaku isle.
The arrest was made on the same day that Japanese Prime Minister Shinzo Abe toured the southern region of Okinawa near the disputed islands in the East China Sea, where he vowed to defend Japan against "provocations".
Abe's comments came in the same week that his government approved a rise in defence spending for the first time in over a decade, explicitly aimed at beefing up defence of the contested island chain.
Chinese government ships have routinely circled the islands since September, when Tokyo nationalised some of them.
Chinese planes have also sporadically breached the airspace over them, stoking the long-running sovereignty row.
The boat "Qiong Yang Pu F8139" was first spotted by a coastguard patrol plane at 7:43 am (2243 GMT Friday) and tried to escape when the Japanese coastguard boat approached it, the JCG branch said in a statement.
Coastguard officers boarded the fishing boat and stopped it soon afterwards. The unidentified captain was arrested at 8:53 am.
The captain told the officers that his boat was hunting corals in the area, public broadcaster NHK reported.
There has been a growing demand for coral jewellery in China, it added.
Unauthorised fishing in Japan's 200-nautical-mile exclusive economic zone can be punished by a fine of up to 10 million yen ($109,000) under Japanese law, the statement said.
China's official Xinhua news agency said the captain, along with two other crew members, was transferred to Miyako island by Japan's patrol vessels, while the other crew members and the boat were still in the place where they were caught.
It was the first time that the captain of a Chinese fishing boat was detained in waters in the Okinawa region since September 2010 when Japan arrested a Chinese trawler captain after he rammed his vessel against two JCG patrol boats in waters around the disputed islands, Kyodo news agency said.
The arrest sparked off a fierce diplomatic protest from Beijing and Tokyo released the captain weeks later without prosecuting him.