China Navy's Nanhai Fleet flotilla is patrolling the Zengmu Reef, the southernmost part [of what it considers to be] the country's territory, and those on board the 3 ships took a ceremonial oath to safeguard sovereignty, reports Xinhua. The Zengmu Reef is a key maritime traffic juncture as well as a strategic spot. The Chinese navy patrols the area, about 50 miles off the coast of Malaysia on a regular basis. Known in English as James Shoal, the reef is claimed also by Malaysia, and the Republic of China (Taiwan).