BEIJING, March 22 (Reuters) - China said on Thursday it had detained 21 Vietnamese for illegal fishing around disputed islands in the South China Sea but Vietnam said the fishermen had been detained in its waters and demanded that China release them unconditionally.
China and Vietnam have overlapping claims to large parts of the South China Sea and various remote islands and reefs and even seemingly minor disputes involving fishermen raise concern about confrontation between the uneasy neighbours.
"Recently, more than 100 Vietnamese fishing boats entered the waters around the Paracel Islands for illegal fishing. Unable to drive them out, relevant Chinese authorities investigated and dealt with a Vietnamese boat and 21 fishermen in accordance with the law," Chinese Foreign Ministry spokesman Hong Lei said.
"China has irrefutable sovereignty over the Paracel Islands, and there is no dispute over this. Vietnamese fishing activities infringe on China's sovereignty and maritime rights," he told a daily news briefing.
"The relevant actions by Chinese authorities are completely proper, law enforcement actions. We hope that Vietnam takes effective measures to earnestly manage and educate its fishermen and stop their invasive fishing."
But Vietnamese Foreign Ministry spokesman Luong Thanh Nghi said it was China that had violated Vietnam's sovereignty.
"Vietnam demands that China immediately and unconditionally release these fishermen and the fishing vessels, and to cease the detention ... of Vietnamese fishermen in the waters of Vietnam," he said.
"A representative from Vietnam's Foreign Affairs Ministry has met with the Chinese embassy to give them a diplomatic note outlining Vietnam's position, and will continue the fight to resolve this matter and protect the legitimate rights of Vietnamese fishermen."
China, the Philippines, Malaysia, Brunei, Vietnam and Taiwan all claim territory in the South China Sea. China's claim is the largest, covering a big U-shape over most of the sea's 648,000 square miles (1.7 million square km), including the Spratly and Paracel archipelagos.
Tension has risen in the region in the past year or so on concern that China is becoming more assertive in its claim to waters believed to be rich in oil and gas and straddling shipping lanes between East Asia and Europe and the Middle East.
China has insisted on handling the disputes on a one-on-one basis rather than multilaterally, a strategy some critics have described as "divide and conquer". China says its sovereignty is indisputable and historically based. (Reporting by Ben Blanchard and Hanoi newsroom; Editing by Robert Birsel)