China raised tensions in the South China Sea on Wednesday by threatening to declare an air defence identification zone (ADIZ) over disputed waters where a tribunal has quashed its legal claim.
The Permanent Court of Arbitration in The Hague ruled on Tuesday that China had “no legal basis” for its “nine-dash line”, which lays claim to almost all of the South China Sea. After considering a case brought by the Philippines, the court ruled against China on virtually every substantive point.
President Xi Jingping responded by saying that China would “refuse to accept” the decision.
On Wednesday, Liu Zhenmin, the vice foreign minister, said: “If our security is being threatened, of course we have the right to demarcate a [air defence identification] zone.”
If such an ADIZ were to be imposed, China would require all aircraft entering the designated airspace to identify themselves. China declared an ADIZ over disputed islands in the East China Sea in 2013, escalating tensions with the United States and Japan.
America then responded by sending two B52 bombers through the ADIZ, without identifying themselves to China.
A new ADIZ in the South China Sea could provoke a similar response. It would also increase tensions not only with the Philippines, but also with other rival claimants in the South China Sea, including Brunei, Malaysia and Vietnam.