During the Battle of Singapore in February 1942, the guns on Blakang Mati were involved in the defence of Singapore. Following the fall of Singapore, a beach on Sentosa was one of the sites where Japanese soldiers killed numerous Chinese during Operation Sook Ching. Part of the island was turned into a prisoner-of-war camp, with about 400 Allied troops and gunners held in the Blakang Mati Artillery Barracks. The island also housed a Japanese air force unit known as Miki Unit and a number of Korean “comfort women” who provided sexual services to Japanese soldiers there.