(VOVworld) - China has begun operation of two light houses it built illegally in Vietnam’s Truong Sa or Spratly archipelago. China announced more construction on reefs illegally held in Truong Sa. Its reclamation of land and artificial islet building were strongly opposed by Vietnam and the world community. The US repeatedly said the illegal construction seriously threatens regional maritime safety and navigation freedom in the East Sea. The US plans to send patrol vessels to the areas 12 miles around Chinese illegal built reefs in the East Sea.