SEOUL (Yonhap) — South Korea and Japan agreed Wednesday to hold regular director general-level talks on the Japanese imperial army’s sexual enslavement of Korean women during World War II in their first meeting on the contentious diplomatic issue, a foreign ministry official here said Wednesday.

The Wednesday meeting between the director generals for Northeast Asian affairs from Seoul and Tokyo — Lee Sang-deok and Junichi Ihara — was the neighbors’ first official negotiations to tackle the sexual enslavement issue, which has long been a vexing source of diplomatic tension between Seoul and Tokyo.

Historians say up to 200,000 women, mainly from Korea and China, were coerced into working at front-line brothels for Japanese soldiers during the war. The grievances of the 55 known South Korean survivors remain unresolved.

During the inaugural meeting, both sides agreed to hold regular monthly talks on the issue, with the next meeting slated for May in Tokyo, the foreign ministry official said.

“In the first negotiations, both sides reaffirmed their basic stances on the (so-called) comfort women issue,” the official said. “Both sides shared the opinion that this issue should be settled speedily in order to remove obstacles in South Korea-Japan relations.”

The details of the next meeting in Japan, including the date and the venue, will be determined through further discussion via the countries’ diplomatic channels, he said.

But the agenda of the regular director-general meeting may expand to cover other bilateral issues like North Korea, the official also said.

The rare meeting on the thorny issue was closely watched for the possibility that it could mark the starting point of mending icy diplomatic relations.

Japan had long dismissed Seoul’s calls to resolve the issue, claiming that all its liabilities stemming from its 1910-45 colonial rule of the Korean Peninsula were settled through a 1965 treaty that normalized their bilateral ties.

Seoul has long said that Japan should settle the comfort women issue “effectively and in a way that is agreeable to the living victims,” including through an apology and compensation.

The comfort women issue has been at the center of current diplomatic tension between the countries, with Seoul saying that their ties can only improve when Japan shows sincerity in resolving issues arising from their shared history.

The icy bilateral relations have put the two countries’ high-level exchanges on hold, with President Park Geun-hye refraining from holding a summit meeting with the Japanese prime minister until last month, more than one year after taking office.

The forced mobilization by imperialist Japan only became widely known in the 1990s, with hundreds of former sexual victims coming forward to reveal the wartime atrocity.

Earlier this year, Abe vowed not to revise Japan’s previous apologies given over the sexual enslavement issue, including the Kono Statement after the administration’s revisionist attempts to modify the sexual enslavement history faced a strong backlash from Seoul and Beijing, which was also a victim of Japan’s imperialism.

The Wednesday meeting also comes ahead of U.S. President Barack Obama’s scheduled visit to Asia, including South Korea and Japan, next week. The U.S. has pressed Japan to refrain from escalating tension with South Korea, given the importance of their trilateral military partnership in Asia.