Another victim of Japan’s wartime sexual slavery died of old age on Wednesday, bringing down the number of total surviving victims to 52.

Lee Hyo-sun, 91, died at a hospital in Changwon, South Gyeongsang Province. She was one of the 238 women who had registered with the government, claiming to have been forced by Japan to serve at frontline brothels during World War II.

Her death underscores the urgency of the wartime human rights issue surrounding the victims, euphemistically called “comfort women.”

Victims have called on Tokyo to offer them sincere apologies and recognize its legal responsibility for the sexual slavery. Seoul has repeatedly urged Tokyo to address the issue as it would remain unresolved forever should all the victims, who are mostly in their late 80s, pass away.

But Tokyo has rejected the demands, arguing all colonial-era issues have been settled under a 1965 pact between the countries that normalized the bilateral relationship. It also claims there is no clear evidence that Japan as a state forcibly mobilized sex slaves during the war.

Despite the growing displeasure in Korea over Tokyo’s lack of atonement, a senior U.S. official said Washington was “gratified” by Prime Minister Shinzo Abe’s congressional speech last month in which he said he would remain true to his predecessors’ apologies for Japan’s wartime atrocities.

“We were gratified to hear him say clearly that he stands by the statements made by the previous Japanese administrations,” U.S. Assistant Secretary of State for East Asia and Pacific Affairs Daniel Russel said during his speech at the Korean Chamber of Commerce and Industry in the U.S. on Wednesday.

Contrary to the U.S.’ positive assessment of Abe’s congressional speech, criticism still continues in Korea over his refusal to include any expressions of repentance in the high-profile speech, such as “heartfelt apology,” an expression his predecessors used in their addresses.

Abe is set to make another speech in August to mark the 70th anniversary of the end of World War II. Observers do not expect him to make any explicit apology for the comfort women issue, although he might use expressions in the speech alluding to Japan’s infliction of “pain” or “suffering” on Asians.

By Song Sang-ho (sshluck@heraldcorp.com)