The statement from the foreign ministry comes just when the Court of Arbitration in the Hague is expected to announce its verdict over territorial disputes in the South China Sea. Since 2013, the Philippines has been seeking UN arbitration to legalize its claims, China has refused to take part, warning it could hurt bilateral ties. 

China has repeatedly detailed the reasons behind its claim. It said China is the first country to discover and name the islands in the South China Sea. As early as the second century BC, ancient Chinese literatures documented maritime activities in the Nansha Islands. The Zheng He Navigational Charts of the Ming Dynasty in the 15th century clearly recorded the Nansha Islands.

In 1948, China demarcated its claims with the nine-dotted line. Starting in the 1970s however, the Phillipines, Malaysia and other countries began referring to the Nansha Islands as included in their own territory. Up until this point, maps published in the Philippines had not laid claim on any of the islands in the South China Sea.