U.S. and Japanese civic groups have announced a joint statement vowing to safeguard a monument in San Francisco that commemorates victims of Japan's wartime sexual slavery.

The city of Osaka in Japan has made repeated requests for the statue to be removed.

The statement was issued by Comfort Women Justice Coalition, a U.S.-based group that led the monument's construction, and a Japan-based organization that has been raising awareness of the comfort women issue.

They said Osaka was trying to remove the symbol representing the pain and memory of the sex slavery victims.

The groups said that if Osaka continues to sever its sister city ties with San Francisco, citizens of the two cities will join hands and fight. 

The monument in San Francisco, erected in September last year, is the first of its kind in a major U.S. city.

It shows three girls from Korea, China and the Philippines standing in a circle while holding hands as sexual slavery victim Kim Hak-sun, who was the very first to give her testimony to the world, looks on. 

Famed local sculpture Steven Whyte created the monument titled “Women's Column of Strength.”