The Osaka Municipal Government said Tuesday that it has sent a document to officially end its 61-year-old sister-city ties with San Francisco over a statue symbolizing the issue of “comfort women,” or those forced to provide sex at Japanese military brothels before and during World War II.

Speaking to reporters at Osaka City Hall, Mayor Hirofumi Yoshimura reiterated his criticism of the comfort women statue and its inscription that says that hundreds of thousands of women were sexually enslaved between 1931 and 1945.

“It’s not based on facts. It’s Japan-bashing,” Yoshimura said. “We shouldn’t continue sister-city relations after we lost mutual trust.”

The city decided last December to sever ties with San Francisco, but refrained from sending official documents to proceed with the breakup, following the sudden death of the U.S. city’s mayor at the time.

After San Francisco’s new mayor, London Breed, took office in July, Osaka sent a letter requesting her to remove the statue, but the new mayor has not responded to it.

Osaka and San Francisco began their sister-city relationship in October 1957 on the basis that the two were coastal cities of similar size. City officials and students from the respective cities have since had numerous exchanges of visits.