China has accused Vietnam of ramming its ships more than 1,000 times in a disputed part of the South China Sea and said while it wants good relations with its southern neighbor, it would not abandon principles to achieve that.

The accusation came after Vietnamese and Philippine troops got together Sunday on a Vietnamese-held island in the disputed Spratlys to play soccer and volleyball, as well as drink beer, in a display of unity that did not go unnoticed in Beijing.

Philippine naval officials billed the event on the Vietnamese-held island as a chance to show the world there can be harmony in the South China Sea despite a web of overlapping claims to the potentially energy-rich waters. The gathering on Southwest Cay in the Spratly archipelago also symbolizes how once-suspicious neighbors are cooperating in the face of China's growing assertiveness in disputed waters.