Two South Korean women who were forced into sexual slavery during World War II have cancelled a planned meeting with Osaka Mayor Toru Hashimoto.
Mr Hashimoto drew international criticism last week when he said that the "comfort women", were "necessary" for Japan's wartime troops.
The two women were worried the meeting would be "politically exploited".
Japan forced an estimated 200,000 women to become prostitutes for troops during the war.
Many of the women came from China and South Korea, but also from the Philippines, Indonesia and Taiwan.
Pang Chung-ja, a supporter of the two women, told reporters that there were fears that Mr Hashimoto would not make a sincere apology during Friday's planned meeting.
"[Mr Hashimoto] has to retract his past comments if he wants to apologise and make us believe it is genuine," she said.
The two women - Kim Bok-dong and Kil Won-ok, who are both in their 80s - did not appear in public.
However, in a statement, they said: "We cannot compromise our painful past as victims and the reality that we still live today for Mayor Hashimoto's apology performance. We don't need to be trampled on again."
The women had requested a meeting with Mr Hashimoto last year, which was rejected, AP news agency reported.
Supporters were said to be sceptical about his motives for agreeing to a meeting after his controversial remarks.
Protestors held a rally outside Osaka city hall on Friday, demanding an apology from Mr Hashimoto, who is also co-founder of the nationalist Japanese Restoration Party.
One supporter, Nobuko Kamenaga, said: "I cannot stand thinking that women were taken against their will, held captive for 24 hours a day, and forced into sex slavery for the Japanese military."
Mr Hashimoto outraged Japan's neighbours when he said on 13 May that the "comfort women" had given Japanese soldiers a chance "to rest".
The Japanese government, which in 1993 issued a formal apology over the issue, has sought to distance itself from his comments.
The US state department has also criticised his words as "outrageous and offensive".