MISSILE DESTROYER LANZHOU, April 17 (Xinhua) -- A Chinese naval fleet patrolled the waters surrounding the Diaoyu Islands on Wednesday, the anniversary of the signing of an unequal treaty between China and Japan in 1895.

Composed of two warships, the Lanzhou missile destroyer and the Hengshui missile frigate, the Chinese People's Liberation Army Navy fleet crossed the Mayako Strait on Tuesday night and arrived at the waters surrounding the Diaoyu Islands early Wednesday morning.

The fleet finished a series of attack and defense drills in the west Pacific area after it sailed out from port.

Zhao Xiaogang, the commander of the fleet, which belongs to the Nanhai Fleet, told a Xinhua correspondent aboard the Lanzhou destroyer that the navy's patrol around the Diaoyu Islands is legitimate and undisputable, as the islands are China's indispensable territory.

The PLA navy patrolled on the day of historical significance, as the Treaty of Shimonoseki between the two countries was signed on April 17, 1895, following China's defeat in the first Sino-Japanese War (1894-1895).

According to the treaty, China ceded Taiwan and its affiliated islands to Japan, and paid Japan as a war indemnity the sum of 200 million Kuping taels.

The treaty was reversed after Japan's defeat in World War II.

Tensions were raised between the two neighboring countries over the islands after Japan's so-called "nationalization" of Diaoyu Island and part of its affiliated islets last year, as well as Japanese politicians' aggressive remarks over Japan-China ties.

In its latest national defense white paper published on Tuesday, China accused Japan of "making trouble over the issue of the Diaoyu Islands."