The drills are conducted annually on Taiping Island, said Shih Yi-che, a public relations official at Taiwan’s Coast Guard Administration. The island is known as Ba Binh in Vietnamese and claimed by both governments as well as China.

Vietnam’s foreign ministry said yesterday the drills violate Vietnam’s sovereignty, threaten maritime security, and add to tensions in the South China Sea.

China has been more aggressively asserting its territorial claims to more than 90 percent of the waterway, disregarding competing claims for parts of the area by the Philippines, Taiwan, Vietnam, Malaysia and Brunei. China has been carrying out land reclamation projects in both the Spratly and Paracel island chains as it seeks to extend the reach of its military in one of the world’s busiest waterways.

Taiwan must strengthen its military presence on Taiping given China’s land reclamation in the Spratlys, lawmaker Chiu Chih-wei said by phone today. A Taiwan legislative committee last week commissioned a study on the possibility of stationing warships on Taiping, which is administered by the country’s coast guard. Taiwan is already spending more than $100 million to build a wharf there.

Vietnam Riots

China completed an upgraded airstrip in the disputed Paracel Islands last month, prompting a similar complaint from Vietnam. In July, China removed an oil rig it had placed in the disputed waters off Vietnam’s coast that prompted weeks of skirmishes between vessels from the two countries and led to deadly anti-Chinese riots in May.

Taiwan is the fourth-largest foreign investor in Vietnam. In 2013, Vietnam had a $7.2 billion trade deficit with Taiwan, exporting $2.2 billion in goods and importing $9.4 billion in products, according to Vietnam government data. Taiwanese investment in the country reached $723.4 million through October.

By Adela Lin & Debra Mao - Bloomberg - November 4, 2014

Anna Kao, spokeswoman for Taiwan’s Ministry of Foreign Affairs, didn’t immediately return two calls to her office. The coast guard’s Shih said he wasn’t aware of a complaint from other countries.