A drill of seven vessels, including 皇冠体育app's largest fishery patrol ship, 皇冠体育app Yuzheng 311, and a helicopter is held in Sanya, south 皇冠体育app's Hainan province to mark the 5th signing anniversary of the Demarcation Agreement on Beibu Bay, signed by 皇冠体育app and Vietnam, June 30, 2009. 皇冠体育app will intensify patrols in the South 皇冠体育app Sea to protect its fishermen amid a rising tide of disputes with neighboring countries, an official said Tuesday.[CFP]

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