PYEONGCHANG, South Korea — Though they face the common challenge of coping with a nuclear North Korea, Japan and South Korea are struggling to bridge a rift over the wartime “comfort women” issue that was supposed to have seen closure with a 2015 accord.

South Korean President Moon Jae-in smiled as he shook hands with Japanese Prime Minister Shinzo Abe ahead of their summit at the Yongpyong ski resort hotel here Friday. But Abe’s expression was more restrained.

Given that Moon took office only last May, Abe had avoided pressuring him on the controversial agreement during their last two meetings. But he took a firmer stance this time, and the leaders spent roughly half of their hourlong talk on the subject.

The agreement is a promise between countries, Abe told Moon, adding that it was an “an internationally and universally recognized principle” that such promises are honored even after a new government takes power, the prime minister later told reporters.

The deal, intended to “finally and irreversibly” put the comfort women issue to rest, was made under Moon’s disgraced predecessor Park Geun-hye, who was impeached following an influence-peddling scandal.

Abe also called for the removal of statues commemorating the women installed in front of the Japanese missions in Seoul and Busan. He argued the memorials violate the 1961 Vienna Convention, which requires host countries to protect the peace and dignity of diplomatic missions.

Abe is adamant that South Korea keep up its end of the deal as uncertainty mounts following the Moon administration’s review of the agreement. Moon told reporters Jan. 10 that he hoped for an additional apology from Tokyo.

“I will say what needs to be said,” Abe told aides before leaving Japan. “It will be a tough meeting for Mr. Moon.”

Some Japanese conservatives opposed Abe’s visit. Voices in Abe’s Liberal Democratic Party warned it would send the wrong message to South Korea and the international community, while conservative groups protested the summit in front of the prime minister’s office.

Yet Abe decided to go, alongside U.S. Vice President Mike Pence, in an effort to salvage Japan’s ties with South Korea. With North Korea launching a charm offensive on Seoul, Abe felt it was imperative to avoid showing the world any further deterioration in bilateral relations. He considered skipping the trip but ultimately chose a face-to-face meeting with Moon instead in order to keep a personal channel for dialogue open.

Much of the rest of the summit focused on North Korea’s nuclear and missile development. The two leaders discussed a trilateral framework with the U.S. to evacuate Japanese nationals from South Korea in the case of an emergency. They also agreed on the importance of establishing a forward-looking relationship between Tokyo and Seoul.

But when it comes to the comfort women deal, Moon’s hands are tied. He repeated his argument that a government agreement cannot solve the comfort women issue, according to the South Korean president’s office. He also stressed that the South Korean people rejected the terms of the 2015 agreement. Moon won his office on the public’s hopes for change and maintains a more than 60% approval rating. The accord is one of many ills from the last administration that he has vowed to remedy.

Abe showed some consideration for Moon’s position and the popular sentiment in South Korea. He steered clear of the comfort women issue during the beginning of their summit, while news outlets were still in the room.

The leaders agreed to hold a trilateral summit with China as soon as possible, meaning Moon may visit Japan as early as April. But as things stand, spring looks unlikely to bring a thaw in Japan-South Korea relations.