'Comfort women': Researchers claim first known film

South Korea has released what it says is the first 
known footage of "comfort women" forced to work as 
sex slaves for Japanese soldiers during World War Two.

Filmed by US troops in China, the clip was found by government- funded researchers at Seoul National 
University in US archives.

The 18-second clip shows several women lined up talking 
to a Chinese soldier.

South Korean activists estimate 200,000 women were 
forced into brothels for Japan's military.

They are believed to have been mainly from Korea, but 
also from China, Indonesia, the Philippines, and Taiwan.

Until now, the only records of women forced into sexual slavery by the Japanese military during World War Two 
had been photographs and survivor testimonials.

The research team says the footage was filmed by  
joint US- Chinese troops in China's Yunnan province which was previously occupied by Japan.

The seven Korean women were freed in 1944 
and the  officer speaking with them has been identified
 as a Chinese captain of the China-US Combined Force, 
the team said.

The issue has long strained the relationship between 
South Korea and Japan over a perceived lack of adequate apology and compensation from Japan.

In 2015, the two countries reached a settlement whereby Tokyo formally apologised and agreed to pay 1bn yen 
($8.3m, £5.6m) to fund victims.

Many Koreans though viewed the apology as insufficient 
and the issue continues to plague ties.

In January, Japan temporarily withdrew its ambassador 
to South Korea over a "comfort women" statue placed 
outside the Japanese consulate in Busan.

A similar statue has also been placed outside Japan's consulate in Seoul, and Tokyo wants both these statues 
to be removed.