Japan’s Foreign Ministry summoned the Chinese ambassador to protest action by a Chinese ship in approaching and apparently threatening a Japanese survey vessel on Monday, some 320 kilometres northwest off Amami Oshima Island, southern Japan, in waters that Tokyo claims as its exclusive economic zone.

Chinese Foreign Ministry spokeswoman Jiang Yu said the ship was acting within its rights.

In the South China Sea, Vietnam is again at loggerheads with China. Both nations are already in a dispute over the Spratly and Paracels Islands, the latter occupied by China.

For Hanoi, China’s ban on fishing in the area “is invalid”, said Foreign Ministry spokeswoman Nguyen Phuong Nga. “Vietnam is going to have diplomatic contact to oppose such acts by China,” she explained.

Both groups of islands are potentially rich in oil and natural gas, but exploration and drilling are impossible because of a number of overlapping territorial claims by China and Vietnam as well as the Philippines, Malaysia, Brunei and Taiwan.

Over the past year, Vietnam has reported cases of its fishing boats and equipment being seized by China.

Whilst the sovereignty dispute simmers with its giant neighbour, Vietnam has announced an US$8.5-billion economic and defence development plan for a string of islands along its resource-rich coastline.

If adopted, China will likely see it as a provocation.