sentences:  During the 1970s the Spratly islands was already a source of dispute for many countries in the region; Malaysia, the People's Republic of China (Communist China), the Republic of China (Taiwan), the Philippines and South Vietnam all claimed sovereignty over all or parts of the islands.In early 1975 the underlying tension between the claimants came to the surface when South Vietnam invaded Southwest Cay, then occupied by the military forces of its wartime ally, the Philippines.In order to lure the Philippines soldiers off Southwest Cay, it was reported that South Vietnamese authorities sent prostitutes to the birthday party of the Philippine military commander on another island.