Yi Ok-seon was a 15-year-old hotel employee in Ulsan, South Korea, when a Japanese official and a Korean accomplice came to put her to work in a military brothel in occupied north-west China.

For three years until the end of the second world war, Yi was forced to have sex with countless Japanese soldiers. Repeated injections of the syphilis treatment compound 606 left her unable to have children. "They dragged us [to the brothels] by force," she said in the House of Sharing, a home for former sex slaves near South Korea's capital, Seoul. "They beat us and swore at us. At the end of the war they abandoned us at the front to die."

Yi, 87, is one of only a few dozen surviving "comfort women", the name given to up to 200,000 women and girls, mostly from the Korean peninsula, who were forced to work in Japanese frontline brothels between 1932 and 1945.

For the past two decades, Japan has officially recognised its role in coercing the women into sexual slavery. But last week, the conservative administration of Shinzo Abe said it would re-examine an apology issued to former sex slaves in 1993 by the then chief cabinet secretary, Yohei Kono.

The findings could be reflected in a report Abe is expected to release next year to mark the 70th anniversary of the end of the second world war.

Japan's resurgent right wing, with Abe at its apex, says there was no official involvement by the wartime Japanese government or military in rounding up women and forcing them into sexual slavery. Instead, it claims the women were willing prostitutes, hired by brokers who took advantage of wartime demand to make easy money.

"The testimonies of comfort women were taken on the understanding that they would take place behind closed doors," the chief cabinet secretary, Yoshihide Suga, said. "The government will consider whether there can be a revision."

The statement is based in part on testimony from 16 women and expresses the government's "sincere apologies and remorse" to the women. But their evidence, sceptics say, was never verified.

Fearing ostracism in their own countries, most of the women took their secret to the grave. Then in August 1991, Kim Hak-soon became the first to testify about her wartime forced prostitution experiences in public. "We must record these sins that were forced upon us," she said.

For the women who spent their formative years serving soldiers in squalid conditions far from home, the Kono statement is a long-overdue expression of remorse that should remain untouched.

Abe's attempts to recast Japan's wartime conduct in a more favourable light have added to tensions over territorial disputes with South Korea and China, and caused concern in the US.

On Wednesday, the US assistant secretary of state, Daniel Russel, called on Japan and South Korea to show restraint over "difficult historical issues" such as comfort women for the sake of regional security. "There is an urgent need to show prudence and restraint in dealing with difficult historical issues," Russel said in prepared testimony for a US Senate hearing. "It is important to handle them in a way that promotes healing. No one can afford to allow the burdens of history to prevent us from building a secure future."

What Abe interprets as a legitimate campaign to vanquish postwar Japan's collective "masochism" over its past, others see as an unsettling attempt to whitewash wartime atrocities.

"I am furious with Abe," said Yu Hui-nam, a South Korean former comfort woman. "Revising the Kono statement would be shameful and absurd."

Yu, who was 16 when she was taken to work in a brothel in the western Japanese city of Osaka, initially refused to return to her hometown in South Korea after the war. "I was ashamed and humiliated," she said. Her relatives persuaded her to return, but she revealed the truth about her past only when other former comfort women started coming forward.

"We were snatched, like flowers that have been picked before they bloom," Yu said. "They took everything away from us. When I think back I remember only tremendous pain. We were not living as human beings."

It is not clear if the planned review will lead to a revision. Abe angered South Korea during his first term as prime minister from 2006-07 when he claimed there was no evidence Japan had coerced the women. But in a recent address to parliament, he conceded Japan had caused great pain in Asia and elsewhere in the past. His government would stick by past apologies and the door was open for dialogue with Beijing and Seoul, he added.

Yi and Yu refused compensation from the Asian Women's Fund, which was set up in 1995 to provide 2m yen (£11,800) each to former sex slaves. The fund drew on private donations, but many women rejected any redress unless it came directly from the Japanese state. The fund was disbanded in 2007 after compensating only 60 of the 207 women the South Korean government had identified as victims.

After Japan's defeat in 1945, Yi remained in China and married a Korean man she had met briefly during the war. They settled in Jilin province, but were separated after he was conscripted to fight in the Chinese civil war.

After returning to South Korea in 2000, Yi was taken in by the House of Sharing, where she lives with Yu and eight other women. "I don't know what Abe thinks he knows about this issue," she said. "It sounds like he is making excuses so that he doesn't have to admit Japan's guilt. It makes me furious when I hear him ignoring what I and other survivors have said."

Yu, 84, refused to discuss her time as a sex slave for much of her life. "I couldn't tell anyone, because I was ashamed," she said. "I never felt joy or happiness, and now the Japanese government is stirring it up again. If [Japan] really is considering going back on its word, then it has no shame. We are human witnesses to the comfort women system. The Japanese should apologise properly to us before we die instead of trying to deny the facts. The world is watching them. We were taken away when we were just teenagers. Nothing can give us back our childhoods."