The Philippines argued at a closed hearing Tuesday that an international court should intervene in its dispute with China over the right to exploit natural resources and fish in the South China Sea.
Although China has declined to participate, the case at the Permanent Court of Arbitration in The Hague is being closely watched by Asian governments and Washington, given rising regional tensions as Chinese naval power grows.
A panel of five judges will hear arguments this week and decide whether the treaty-based court has jurisdiction.