NANJING, May 10 (Xinhua) -- Researchers have identified another five victims forced into sexual slavery by Japanese troops during WWII in central China's Hunan Province, bringing the total number of the survivors on the Chinese mainland to 18.

Since May, five "comfort women," including the oldest victim Liu Nianzhen, 102, were found, according to the Research Center for Comfort Women at Shanghai Normal University and the museum on the site of a "comfort women" station in Liji Lane, Nanjing, capital of east China's Jiangsu Province.

Liu, born in 1918, was brutally abused by the Japanese army during the war and as a result, became infertile. She still fears the Japanese and is reluctant to let anyone touch her, researchers said. Liu adopted a son from her younger brother, who now takes care of her.

Based on on-site visits of the once Japanese military garrisons and cross-examinations, the researchers confirmed the victims' experiences.

Early this month, two 99-year-old "comfort women," Wei Shaolan and Tang Genzhen, died one after another, arousing public concern over the victims of the wartime sex slavery.

Currently, Chinese researchers and institutions have been racing against time to search for surviving "comfort women."

Hunan has the largest number of confirmed surviving "comfort women" in China, as the Japanese army captured a large number of local women during the province's fierce fights against Japanese aggression during the WWII, said Su Zhiliang, director of the research center.

Women forced into sexual slavery by the Imperial Japanese Army before and during WWII were called "comfort women." Research shows some 400,000 women in Asia were forced to be "comfort women" for the Japanese army during World War II, nearly half of whom were Chinese.