U.S. Democratic Leader Nancy Pelosi plans to visit South Korea next week, diplomatic sources said Thursday, amid hopes she could play a role in helping resolve tensions between Seoul and Tokyo over the issue of Japan's sexual enslavement of women during World War II.

Pelosi will lead a delegation of U.S. House lawmakers on the visit to South Korea on April 1-3. Seoul is part of a regional trip that will also take her delegation to Myanmar, Vietnam and Japan, the sources said. She was to depart on the trip on Thursday.

While in Seoul, she is expected to pay a visit to President Park Geun-hye and meet with South Korean National Assembly Speaker Chung Ui-hwa.

Pelosi was the speaker when the House of Representatives adopted a landmark 2007 resolution on Japan's wartime sexual slavery that called on Tokyo to formally acknowledge, apologize, and accept historical responsibility for the atrocity.

Historians estimate that up to 200,000 women, mainly from Korea, which was a Japanese colony from 1910 to 1945, were forced to work in front-line brothels for Japanese soldiers during World War II. But Japan has long attempted to whitewash the atrocity.

The sexual slavery issue has been the biggest thorn in frayed relations between Japan and South Korea, with Seoul demanding Japan take steps to address the grievances of elderly Korean victims of the atrocity and Japan refusing to do so. (Yonhap)