(Reuters) - Taiwan is considering stationing armed vessels permanently on a disputed South China Sea island, officials said, a move bound to renew friction in a region claimed almost wholly by China, with Vietnam already dismissing such a plan as "illegal".
The potentially energy-rich Spratly islands are one of the main flashpoints in the South China Sea, with claims also from Malaysia, the Philippines and Brunei, and are closely watched by the United States after China placed a giant oil rig in nearby waters also claimed by Vietnam.
Itu Aba, also known as Tai Ping, is the only island in the Spratlys large enough to accommodate a port - currently under construction. Taiwan had previously said the port, expected to be completed in late 2015, would allow 3,000-tonne naval frigates and coastguard cutters to dock there.
Officials at Taiwan's Coast Guard, which administers Itu Aba, and Taiwan's Ministry of National Defense, which stations troops there, said the port could become the permanent home of armed vessels.
"We are discussing this possibility," said Chen Yeong-kang, chief of Taiwan's navy, acknowledging that "it is a very sensitive issue".
Shih Yi-che, head of communications at Taiwan's Coast Guard, said: "The purpose of this action would be to promulgate the Republic of China's sovereignty and power in defending our territory around Tai Ping Island."
Rivals China and Taiwan share claims to virtually the entire South China Sea, a legacy of the Chinese civil war when the Communists split from the Nationalists and took control of the Chinese mainland in 1949. The Nationalists settled on Taiwan, and as the "Republic of China", still claim to be the legitimate rulers of greater China.
China, which claims Taiwan as a renegade province and has not ruled out the use of force to bring it under its control, issued a sanguine response to Taiwan's plan.
"Taiwan and the mainland are both part of one China. Relevant activities by Chinese people in the Spratly islands and its nearby seas, including on Tai Ping, are beyond reproach," China's Foreign Ministry said in a statement sent to Reuters.
Experts believe China prefers Itu Aba to remain under Taiwan's control rather than fall into the hands of other rivals, given its ultimate goal of reunification.
But Taiwan ships on permanent call in the Spratlys would represent a new headache for Communist Party rulers in Beijing as they grapple with weeks-long pro-democracy protests in southern Hong Kong and face separatist calls in far-western regions of Tibet and Xinjiang.
Itu Aba is Taiwan's only holding in the disputed region, but it boasts the larger of two landing strips in the archipelago and is the only island with its own fresh water supply, making a long-term presence possible.
"It reinforces the trend of increased para-military activity across the South China Sea," Ian Storey, a South China Sea expert at Singapore's Institute of South East Asian Studies, said of Taiwan's plan.
"I would fully expect we'll see Vietnam make some kind of pro-forma protest, followed by the Philippines."
The ships would mainly be used for rescue and maintenance, though they would be equipped with weapons systems, Shih and an official at the Ministry of National Defense said. It was not immediately clear how many ships would be stationed there or when a final decision would be made.
Taiwan has not taken sides with China in the South China Sea, despite the historical ties, given the political mistrust between them - and because of its need to maintain good relations with its biggest ally and arms supplier, the United States, a vocal critic of Beijing's policies in the disputed waters.
A senior commander in the Philippine navy told Reuters that Taiwan's plan would lead to increased military activity in the Spratlys and that it could raise the possibility of "incidents", while a spokesman for Vietnam's Ministry of Foreign Affairs called any such move "illegal and groundless."
Malaysia has five permanent stations in the Spratlys and there is always at least one navy ship at a station, a navy spokesman said.