Updated

Japan has expressed strong regret over San Francisco's decision to give formal city property status to a statue commemorating women who worked in military-backed brothels for Japanese troops during World War II, with Osaka declaring it will terminate its 60-year sister-city ties.

Osaka Mayor Hirofumi Yoshimura said the signing of legislation making the memorial public property "destroyed trust."

The statue was erected by California's Korean, Chinese and Filipino communities.

Japan's government denies that the women were forced into sexual slavery and says the statue wrongly blames Japan.

Chief Cabinet Secretary Yoshihide Suga said San Francisco's decision challenges Japan's position and is "extremely regrettable." He said similar statues that have been built in various countries interfere with a 2015 agreement with South Korea to resolve the historical dispute.