Nancy Pelosi, the U.S. House minority leader, called on Japanese Prime Minister Shinzo Abe Thursday to apologize for the sexual slavery of Korean and other Asian women during World War II.

“We have been clear about what we’d like to hear about comfort women,” Pelosi told reporters when asked about her view on Abe’s planned congressional speech in Washington later this month. “I hope that a statement will be made to free (Japanese) people from this burden of the issue of comfort women.”

She made the remarks soon after she met with Foreign Minister Yun Byung-se.

The Ministry of Foreign Affairs said they have exchanged ideas concerning North Korea as well as the relationship between South Korea and Japan.

It added Yun asked Pelosi for the U.S. Congress’ cooperation in encouraging Abe to deliver an apology over the history including sex slaves, as well as positive messages to South Korea and its surrounding countries.

South Korea has repeatedly pressed Japan to face up to history, especially over the elderly Korean women who were forced into sexual slavery for Japanese soldiers during World War II.

Still, there is no sign of progress in resolving the issue that hinders close relations between South Korea and Japan, two key U.S. allies in Asia.

Abe described the sex slave issue as “human trafficking” without specifying the perpetrator in a recent interview with the Washington Post.

“I hope that he apologizes in some format, it does not have to be before Congress,” Pelosi said. “I would imagine if the prime minister is going to make a statement, he probably do that in his own country rather than somebody else’s country.”

Also Thursday, Pelosi met with South Korean President Park Geun-hye and shared the need of resolving the issue of sex slaves, according to Park’s office.

Park told Pelosi that the issue has gained urgency as the victims are in their late 80s, according to Park’s office.

In 2007, more than 120 South Korean victims were alive, but the number has since dropped to 55, with their average age standing at 88.

Pelosi, who led a 10-member bipartisan delegation to South Korea, was the House 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 its past atrocities.

South Korea hopes to help the U.S. lawmaker better understand the issue of Japan’s wartime sex slaves ahead of Abe’s address to a joint session of the U.S. Congress.