China has asked the Philippines to withdraw a Filipino coast guard ship and an archaeological research vessel from a disputed shoal. It also has ignored a Philippine proposal to bring the problem to a U.N.-linked tribunal for arbitration.

China and the Philippines have agreed to settle the dispute diplomatically but have insisted on their ownership of the Scarborough Shoal in the South China Sea. Two Chinese surveillance ships have been facing off with a Philippine coast guard vessel in the area since last week.

Philippine Foreign Secretary Albert del Rosario has asked China to bring the dispute to the International Tribunal on the Law of the Sea for arbitration.

The Chinese Embassy ignored the proposal Tuesday and asked the Philippines to withdraw from the shoal.