AFP/ DPA

TOKYO/ PHNOM PENH JAPAN summoned the Chinese ambassador on Wednesday as a diplomatic row flared up after three Chinese patrol boats approached a chain of islands at the centre of a bitter territorial dispute.

The Japanese coastguard said the vessels entered Japanese waters around the islands in the East China Sea known as Senkaku in Japanese and Diaoyu in Chinese early on Wednesday.

That prompted Japan’s foreign ministry to summon the Chinese ambassador in protest, said Chief Cabinet Secretary Osamu Fujimura.

“It is clear that historically and legally Senkaku is an inherent territory of Japan,” the government’s top spokesman told a regular press briefing, adding that Beijing’s envoy had been summoned over the vessels.

The trio of Chinese ships were identified as Yuzheng 35001, Yuzheng 204 and Yuzheng 202, the coastguard said. The crew of the vessels, which have since left the islands’ immediate vicinity, initially rebuffed Japanese orders to leave.

“We are conducting official duty in Chinese waters. Do not interfere. Leave China’s territorial waters,” the crews said, according to the coastguard.

The incident comes amid increasingly sore relations over the islands, which lie in rich fishing grounds and may contain valuable mineral reserves, with Tokyo earlier saying it may buy the chain from their private Japanese owner.

The Tokyo metropolitan government said it had already collected more than 1.3 billion yen ($16.3 million) in donations from across the country to fund the purchase.

Beijing has shot back that Japan has no right to buy the islands.

Meanwhile, China’s Foreign Minister Yang Jiechi reasserted on Wednesday that the contested Diaoyu islands in the East China Sea belonged solely to Beijing.

Yang’s comments came in a statement issued after he met Japan’s Foreign Minister Koichiro Gemba on the sidelines of an Association of South-East Asian Nations (ASEAN) forum taking place in Phnom Penh.

The statement said Yang had “reaffirmed China’s principled position” on the islands and “stressed that Diaoyu Islands and their affiliated islets have always been China’s territory since ancient times, over which China has indisputable sovereignty.” There was no immediate response from Japan. Yang did not speak to reporters when entering a meeting later on Wednesday.

The seabed near the uninhabited islands, known to Japan as the Senkaku islands, is thought to be rich in natural gas. China, Japan, Taiwan and other neighbouring countries all claim the area.

The statement came as ASEAN ministers continued to seek agreement on a mechanism to resolve disputes peacefully between its members and China over tracts of the South China Sea.

Tensions between China and two ASEAN nations - Vietnam and the Philippines - have risen this year over Beijing’s claims.

ASEAN states Brunei and Malaysia also assert ownership over some areas of the South China Sea, as does Taiwan. The statement echoed another released by China on Saturday when it rebuffed Japan for suggesting that it sell the disputed islands.