A South Korean survey ship has moved out of Japanese-claimed waters near a group of disputed islets, Japan's coast guard said Wednesday, following strong protests from Tokyo.

The ship, which began a maritime survey on Monday, entered waters that Japan says fall within its exclusive economic zone early Wednesday despite a demand from Tokyo that Seoul stop the operation.

The South Koreans were surveying the waters surrounding a group of rocky islets called Takeshima in Japan and Dokdo in Korea, which lie roughly halfway between the two countries and over which the two countries have a long-running ownership dispute.

The "Haeyang 2000" left Japan's claimed territorial waters, about 22 kilometers from the islets, at around 2 PM (05:00GMT), the coast guard said in a statement.

But the vessel remained within Japan's exclusive economic zone, where a Japanese patrol boat was monitoring it, according to Japan Coast Guard official Naoki Mori.

The South Korean ship entered the Japanese-claimed waters at 6:41 AM Wednesday (21:41 GMT Tuesday). It was intercepted by a Japanese patrol boat soon after, the coast guard said.

Japan demanded that South Korea halt the operation, but the survey ship continued its work in the disputed waters.

"That South Korea carried out the maritime survey despite protest from Japan... is extremely regrettable and we demand its immediate termination," Chief Cabinet Secretary Shinzo Abe told reporters Wednesday.

South Korea, meanwhile, claimed the Japanese patrol boat had entered South Korean waters.

South Korea's Yonhap News agency reported that the survey was supposed to be completed Wednesday, but Kim Ok-soo, an official at the National Oceanographic Research Institute, said the survey will continue until July 17.

(China Daily July 6, 2006)