The world's first ever footage of Korean sex slaves used by Japanese soldiers during WWII has emerged.

Grainy black and white footage from 1944 shows seven bare-footed women outside a brick house said to be a military-run brothel in occupied China as it was liberated from the Japanese by Allied forces.

One woman in a dirty blouse is seen talking to a Chinese officer, others stare nervously at the ground and one, who appears to be pregnant, gently touches her bump.

Until now, photographs and accounts from survivors - labelled 'comfort women' by Japanese forces - have been the only records of Korean sex slavery.

The world's first ever footage of Korean sex slaves used by Japanese soldiers during WWII shows the women being 'liberated' by American and Chinese forces

Grainy black and white footage from in 1944 shows seven bare-footed women outside a brick house said to be a military-run brothel in Songshan, China

But after a two year trawl through US archives, researchers uncovered footage which appears to show sex slaves at Songshan, Yunnan Province, as US-China Allied Forces reclaimed Songsan from the Japanese.

A team from Seoul University and Seoul Government matched the footage outside the building to pictures and identified the women by their clothes and facial appearance.

SungKongHoe University professor Kang Sung-hyun, who participated in the study, said: 'Their appearance, such as the bare feet, suggest they were enslaved.

'Due to a long-standing dispute over Japan's wartime sexual slavery, it became crucial to come up with evidence.

'This video clip will strengthen the admissibility of evidence behind wartime sex slavery.'

Professor Kang said the footage was discovered at the US National Archives and Records Administration where it had been gathering dust for some 70 years.

The clip tied in with wartime records showing a dozen sex slaves being captured in Songshan by the allied forces in September 1944.

One woman in a dirty blouse is seen talking to a Chinese officer, others stare nervously at the ground

Up to 200,000 women, mainly from former Japanese colony Korea, are believed to have been forced into sex slavery (historic photo of US sailors gathering outside a 'comfort station' in Yokosuka, south of Tokyo

THE TRAGIC HISTORY OF KOREAN 'COMFORT WOMEN' Most historians agree that as many as 200,000 women, mostly from Korea, were forced to work in Japanese military brothels during World War II. The plight of the women is a hugely emotional issue which continues to strain relations between Korea and Japan today. For many South Koreans, the issue symbolises the abuses of Japan's 1910-45 colonial rule over the Korean peninsula. Most historians agree that as many as 200,000 women, mostly from Korea, were forced to work in Japanese military brothels (pictured) during World War II The term 'comfort woman' comes from the Japanese euphemism 'jugun ianfu' which refers to women, of various ethnic and social circumstances, who became sex slaves for the Japanese troops before and during WWII. Military brothels existed across the Asia Pacific region in areas occupied by the Japanese forces. The women forced to work there were forced to have sex with up to 50 Japanese soldiers a day as they were raped and sexually assaulted during the Second World War Though around 80 per cent were Korean, women from Japan, Taiwan, the Philippines, Indonesia, Burma and the Pacific islands were also used as comfort women, according to a San Francisco State University report. The authorities believed the comfort system would enhance the morale of the military and help prevent soldiers from committing sexual violence toward women of occupied territories, which became a real concern after the infamous Nanjing Massacre in 1937. They were also concerned with the health of the troops, which prompted close supervision of the hygienic conditions in the comfort stations to help keep STDs under control. Though around 80 per cent were Korean, women from Japan, Taiwan, the Philippines, Indonesia, Burma and the Pacific islands were also used as comfort women. Pictured; A Chinese woman used in Japan's 'comfort battalions' is interviewed by an Allied officer Meanwhile many of the women who worked in 'comfort stations' during WWII were given repeated injections of the syphilis treatment compound 606, which left many of them unable to have children. After the war, many of the women were brutally slaughtered and their story was untold until 1991. The only military tribunal concerning the sexual abuse of comfort women took place in Batavia - now Indonesian capital Jakarta - in 1948. Several Japanese military officers were convicted for having forced 35 Dutch women involved in the case into comfort stations. The issue only began to emerge in Korea only in the late 1980s. The Japanese government admitted deception, coercion and official involvement in the recruitment of comfort women in August 1993, but critics said they needed to go much further. The plight of 'comfort women' during WWII is a hugely emotional issue which continues to strain relations between Korea and Japan today. Pictured: Former comfort women, in yellow, shout slogans during an anti-Japan rally in Seoul In May this year, Japanese Prime Minister Shinzo Abe met with a senior South Korean envoy as the two countries continued to lower tensions over Tokyo's wartime use of 'comfort women'. The special envoy dispatched by South Korea's new President Moon Jae-In said Seoul wants to improve relations which have been hindered by the memory of Japan's harsh colonial rule of the Korean peninsula. Abe struck a conciliatory note, saying: 'With the new president, I wish to build future-oriented Japan-South Korea relations.' In what both governments hoped was a major step forward, the two countries had agreed in 2015 to a deal designed to end a row over the issue. Advertisement

The allied forces interrogated them before they were released back to the Koreans in 1946.

The women and the place captured in the clip also matched those shown in a set of photos taken by Edwards C Fay, a private of the US Army Signal Corps' 164th Photographic Unit, which were uncovered in 2000.

Researchers believe the names of the women in the video are on the list of the former Korean sex slaves who were captured in China, including former sex slave Park Young-shim who is believed to be the pregnant woman.

Seoul Mayor Park Won-soon said: 'As unfortunate history must also be recorded and remembered so that it is not repeated, the Seoul government will focus all of its capacity and resources in documenting history and setting things right.'

The Japanese military's use of sex slaves during WWII is a controverisl issue, with up to 200,000 women, mainly from former Japanese colony Korea, are believed to have been forced into sex slavery.

Many 'comfort women' were given repeated injections of the syphilis treatment compound 606, which left many of them unable to have children. Pictured: Captured women in Myitkyina, Myanmar, in August 1944

'Comfort women' were forced to have sex with up to 50 Japanese soldiers a day. Pictured: Comfort women during the Allied reoccupation of the Andaman Islands in 1945

In December 2015 Japan's Prime Minister Shinzo Abe apologised to Korean women used by soldiers as sex slaves and pledged more than £5.37m to help the victims.

He described the 'incurable physical and psychological wounds' suffered by 'comfort women' co-erced into military run brothels.

The women and the South Korean government have fought a decades-long battle for an adequate apology for the treatment of the sex slaves.

Many feel the apology was inadequate and in January this year a South Korean Buddhist monk died after he set himself on fire to protest the country's deal with Japan on former sex slaves.