TOKYO - A protest ship from Taiwan joined around a dozen state-owned Chinese vessels in waters near Japan-administered islands on Friday as a territorial row rumbled on.
The Taiwan-registered ship was spotted 44 kilometres (28 miles) off Uotsurijima, the largest island in a group known as Senkaku in Japan and Diaoyu in China.
Japan controls the islands though China and Taiwan also claim ownership.
"This ship is not a government-owned vessel. By speakers and wireless communications we are warning the ship not to enter our territorial waters," a spokesman for the coastguard's Okinawa branch said by telephone.
Under international law, territorial waters extend up to 12 nautical miles from a shoreline.
"The ship is insisting that the islands are part of their territory. They told us not to stand in their way."
Banners reading "Protect Diaoyu" and "Get back Diaoyu" in Chinese were seen on board, the coastguard said in a press release.
It was the first time since July that a protest ship from Taiwan had been seen in waters near the island group.
A total of 13 vessels from China's maritime and fisheries authorities were spotted in waters off the disputed islands.
Four of them moved into the so-called contiguous zone, a band a further 12 nautical miles from territorial waters, off the island of Taishojima, in early afternoon and remained there as of 0600 GMT, the coastguard said.
State-owned Chinese ships have gone in and out of the contiguous zone, briefly entering territorial waters on Tuesday, since the row flared up again when Japan nationalised three of the islands on September 11.
Violent anti-Japan demonstrations spread through major cities in China for eight days but practically vanished on Wednesday, reportedly under orders from Chinese authorities.
On July 4, a boat carrying activists and four patrol boats from Taiwan entered territorial waters around the islands.