A boatload of Taiwanese activists tried to approach disputed uninhabited islets controlled by Japan in the East China Sea early Thursday but was warned away by Japan Coast Guard ships before managing to enter Japan's territorial waters, JCG officials said.

The 50-ton Quanjiafu No. 6, a squid boat, was apparently seeking to land activists on one of the Senkaku islets to protest Prime Minister Junichiro Koizumi's Tuesday visit to Tokyo's war-related Yasukuni Shrine on the anniversary of Japan's surrender, according to the officials. Taiwan also claims the rocky islets, and calls them Tiaoyutai, as does China, which refers to them as Daioyu.

The ship, which was believed to have left a Taiwanese port at 12:15 a.m., was first spotted by JCG ships at 5:11 a.m., 72 km west-southwest of Uotsuri.

Around 7:02 a.m, the ship stopped 33 km off Uotsuri. It turned back after JCG ships warned it off through loudspeakers, the officials said.

The JCG followed the Quanjiafu, whose occupants threw stones at the coast guard ships, the JCG officials said, adding the vessels were not hit and no one was hurt.

The JCG stopped tailing the Quanjiafu at 8:59 a.m. when it crossed the median line demarcating Japan's claimed exclusive economic zone.

Koizumi's annual visits to Yasukuni Shrine, which honors 14 Class-A war criminals as well as 2.47 million war dead, have angered many Taiwanese as well as China and South Korea.

The U.S. returned the islets to Japan in 1972.