Tensions are escalating anew in the East China Sea, as Japan’s coastguard fired water cannon to repel a Taiwanese fishing boat, entering the waters around a group of disputed islands.

The boat, carrying seven people including four Taiwanese activists, gave up a plan to land on the East China Sea islands after being blocked by Japanese coastguard vessels as it sailed within 17 nautical miles of the archipelago.

The activists, who set off in the early hours, had hoped to place a statue of the Goddess of the Sea on the islands, to protect Taiwanese fishermen in the area.

They had also intended to "maintain sovereignty" in defiance of Japan's control, said Hsieh Mang-lin, the Taiwanese chairman of the Chinese Association for Protecting the Diaoyutais (Diaoyu Islands).

As Japan's coastguard fired the water cannon on the Taiwanese boat, Taiwan's coastguard on routine patrol in the area came to the rescue of the activists.

"We don’t provoke, we don’t enter conflict, but we also don’t turn from our firm stance that we will not back down from safeguarding our sovereignty," Taiwan coast guard commander Chen Shi-chuan said afterwards.

The disputed islands, in an area where the seabed is believed to harbour valuable mineral reserves, are known as Senkaku in Japanese and Diaoyu in Chinese. Both China and Taiwan claim them.

As the standoff unfolded, three Chinese surveillance vessels were positioned a few nautical miles off, the Taiwanese coastguard said.

Regional friction

The incident came at a time of growing regional concern over the intensified friction over the islands between China and Japan, with both Beijing and Tokyo recently scrambling fighter jets to assert their claims to the area.

Some fear the fight between Japan, Taiwan and China over the islands could lead to an all out war.

Last September, coastguard vessels from Japan and Taiwan also exchanged water cannon barrages after dozens of Taiwanese boats were escorted by patrol ships into the islands' waters.

The rocky island outposts have been the scene of a diplomatic tussle between Japan and China for months Japan's government nationalised three of them in September by taking them out of private Japanese ownership.

Since then, Beijing has repeatedly sent government ships into the waters.

In December a Chinese government plane overflew them, leading Japan to scramble fighter jets.

Earlier this month both militaries had jets in the area and Japanese newspapers have reported that Tokyo is mulling allowing its pilots to fire warning shots.