Top U.S. government officials have expressed “growing concerns” that China is seeking to expand its sphere of territorial control in the South China Sea, and this is fuelling insecurity and instability throughout the region.

In his testimony to the House of Representatives’ Subcommittee on Asia and the Pacific Daniel Russel, Assistant Secretary of State for the region said, “This pattern of behaviour in the South China Sea reflects incremental effort by China to assert control over the area contained in the so-called 'nine-dash line' despite objections of its neighbours and despite the lack of explanation or apparent basis under international law regarding the scope of the claim itself.”

The focus of Washington’s ire, the “nine-dash line,” is Beijing’s map representation of its maritime territorial claims in the South China Sea, a boundary that is said to include nearly 90 per cent of the 3.5 million square kilometre sea.

The territorial claim is considered problematic because in addition to China, the Philippines, Vietnam, Taiwan, Malaysia and Brunei have demanded access to the waterway that is said to provide “ten per cent of the global fisheries catch and carries $5 trillion in ship-borne trade.”

Speaking on Capitol Hill Mr. Russel said this week, “Any Chinese claim to maritime rights not based on claimed land features would be inconsistent with international law,” adding, “China could highlight its respect for international law by clarifying or adjusting its claim to bring it into accordance with international law of the sea.”

The discussion of China’s claims in the South China Sea come in the wake of Beijing’s declaration of an Air Defence Identification Zone (ADIZ) over the East China Sea in December 2013, a move that led to a spike in tensions linked to a territorial dispute with Japan over the Diaoyu/Senkaku Islands, included within the declared ADIZ.

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