A Chinese ship rammed and sank a Vietnamese fishing boat off the coast of Vietnam on Sunday, according to Vietnam's foreign ministry.

Ten fishermen were on board, Vietnam News reported. They were rescued by nearby Vietnamese boats approximately 17 nautical miles from an oil rig owned by China near the Paracel Islands.

Anti-China protests took place earlier this month in Vietnam after China built the rig off the coast of Vietnam, and there were skirmishes between coast guard vessels belonging to both countries earlier in the same month. Whereas Vietnam says China is violating international law and stability, China says it owns the territory in which it built the rig.

According to Bloomberg News, China is expanding the reach of its navy to support its claims to territory in the South China Sea, which are based on a map devised in 1947. China and Vietnam both claim the Paracel Islands, and the Association of Southeast Asian members Brunei, Malaysia and the Philippines have claims to other areas in the South China Sea.