Two Japanese landed on the Diaoyu Islands at around 9:30 a.m. (0030 GMT) Tuesday, Chief Cabinet Secretary Osamu Fujimura told reporters.

The Diaoyu Island [File photo]

"The (Japan) Coast Guard said they have already left," Fujimura said at a regular press briefing.

The two people arrived at waters near the Diaoyu Islands by boat, then swam ashore on the island, according local media reports.

Tensions have mounted between China and Japan since Sept. 10 when the Japanese government announced the "purchase" of the Diaoyu Island and its affiliated Nan Xiaodao and Bei Xiaodao, which have been China's inherent territory.

The Diaoyu Islands have been China's territories since ancient times.

The islands had been put under the jurisdiction of China's naval defense since the early era of the Ming Dynasty (1368 AD-1644 AD). Japan stole the islands from China during the First Sino-Japanese War in 1895.

In accordance with the Cairo Declaration and the Potsdam Proclamation released at the end of the Second World War, the Diaoyu Island and affiliated islets should be returned to China.

In 1971, Japan and the United States signed the Okinawa Reversion Agreement, which arbitrarily included the Diaoyu Islands in the territories and territorial waters to be reversed to Japan. The Chinese government has, from the very beginning, firmly opposed and never acknowledged such backroom deals between Japan and the United States concerning Chinese territories.