Violent confrontations could escalate between South Korea and Chinese boats found fishing in its waters after the US ally sanctioned a greater use of force, including the use of firearms, to control its sea border. The threat of lethal force comes as China publically berated the US over its operations close to artificial islands Beijing has built in the South China Sea, and its plan to deploy a missile defense system to South Korea.

China’s ambassador was summoned by South Korean officials to protest the latest clash off the Korean peninsula’s west coast, in which a coastguard patrol boat sank last week after being rammed by a Chinese fishing vessel. There were no reported casualties. Three Chinese fishermen were killed last month when a fire broke out on their boat after a South Korean coastguard threw flash grenades into their cabin. READ MORE