The Allied Forces who participated in World War II have made testimonies on women who were sexually enslaved by Tokyo during the war, a recent study showed Wednesday.

In the study by Tessa Morris-Suzuki, professor of Japanese History at Australian National University, a recorded testimony of Angus McDougall, a former Australian serviceman, shows how a group of girls were transported to Japanese army brothels "in the same hellish conditions" as soldiers.

"These girls, McDougall recalls, were not Japanese but a multi ethnic group," the report said.

Frederick Arblaster, an Australian translator who assisted the troops with post-surrender interrogations, once asked a Japanese officer about the women he encountered, only to hear that they were Red Cross and hospital nurses.

Remembering the women's clothes and powdered faces, Arblaster regretted having failed to ask more about them, according to the report.

The report is based on spoken, written and visual records left by allied troops and civilians on comfort women, held by the Imperial War Museum in Britain and the Australian War Memorial.

"The material presented here is, I think, just the tip of an iceberg of third party testimony to the history of the comfort women'," Morris-Suzuki wrote in the report. "Much has surely been lost, or soon will be, as the generation with personal memories of the war disappears." 

The report, titled "You Don't Want to Know About the Girls? The 'Comfort Women,' the Japanese Military and Allied Forces in the Asia-Pacific War," was published at the Asia-Pacific Journal in August 2015.

Its Korean-translated version, the first of its kind to introduce testimonies by allied forces, will be available at a local quarterly journal at the end of this month.

"The study on Japanese comfort women has relied heavily on the testimonies made by the victims so far," said Kim Min-cheol, a researcher at the Center for Historical Truth and Justice.

"As (Morris-Suzuki's) report confirmed the existence of Japanese sex slaves in allied soldiers' testimonies, a follow-up study is important," he added.

The issue of the "comfort women," a euphemistic term for the former sex slaves, has been a major thorn in South Korea and Japan's relations.

In December, Seoul and Tokyo reached a landmark accord to end their dispute with Japan's acknowledgment of responsibility, an apology from Japanese Prime Minister Shinzo Abe and Japan's offer of 1 billion yen ($8.5 million) in reparations to the victims.

The deal sparked protests among some victims and their supporters, who said the government failed to hold Japan legally accountable in the deal and failed to consult with them beforehand.

Historians estimate that more than 200,000 women, mostly from Korea, were forced to work in front-line brothels for Japanese soldiers during the war. Korea was under Japanese colonial rule from 1910 to 1945. (Yonhap)