Photo/IllutrationSouth Korean President Moon Jae-in, right, meets with Toshihiro Nikai, secretary-general of the ruling Liberal Democratic Party, in Seoul on June 12. (Pool)

SEOUL--With no letup in North Korea's military provocations, South Korea can ill afford to let relations slide with Japan over the "comfort women" issue.

That explains the apparent turnaround in a campaign pledge by South Korea's new president, Moon Jae-in, to invalidate and renegotiate a landmark accord on the matter if he took office.

Several sources with the inside track on Japan-South Korea ties said that Moon has now decided to undertake an assessment of the process that led to the December 2015 agreement by Tokyo and Seoul to resolve the decades-old thorn in bilateral relations, rather than simply scrap it.

Moon's intention is to calm public anger over the terms of the agreement that was hailed at the time as a "final and irreversible resolution" of the dispute.

"The inclusion of promises to invalidate and renegotiate the agreement in the campaign platform was strongly influenced by the need for consideration of citizens groups (opposed to the bilateral agreement)," one source said.

As North Korea has not shown any sign of ending its almost weekly ballistic missile tests in the Sea of Japan, the last thing Seoul needs is for its relations with Tokyo to worsen, sources said.

Another factor concerns the deployment of the U.S. military's Terminal High Altitude Area (THAAD) missile system in South Korea that is aimed at intercepting attacks from North Korea. The deployment, agreed to by Moon's predecessor, is unpopular among many South Koreans.

From a national security standpoint, Seoul needs to be able to work closely with Tokyo in dealing with North Korea, especially as relations with Washington are under strain over the THAAD deployment.

The Moon administration has yet to clarify the path it plans to take on the comfort women issue.

However, officials have made clear they do not want differences with Japan to impact on national security policy, given North Korea's bellicose posturing.

Conducting an assessment of the negotiation process behind the bilateral agreement could allow the administration to quell public anger, as well as give it time to discuss a compromise with Japan to push forward with implementation of the agreement.

Several sources said specific work on the assessment would begin after a planned meeting in July between Moon and Prime Minister Shinzo Abe.

Officials directly involved in the negotiations will be questioned, and records from that period examined, to determine the process behind Japan's decision to provide 1 billion yen ($9 million) in government funds to support former comfort women who were forced to provide sex to wartime Japanese soldiers.

The assessment will also try to unravel whether any agreement was reached on removing a statue representing the comfort women from near the Japanese Embassy in Seoul. Tokyo regards the statue as an affront.

The sources said no preconditions would be attached to the assessment, and that the bilateral agreement will remain in place until the process is completed.

The work will be handled by officials in the presidential office and not include any assembly members. This is because the bilateral agreement is regarded as a political pledge that is not related to any treaty or relevant laws.

While the assessment is carried out, the Moon administration is expected to chart its own course for proceeding with the comfort women issue while striving to build a relationship of trust between Moon and Abe.

Seoul has taken other recent steps to avoid causing friction in ties with Japan.

When nominating a new minister of gender equality and family on June 13, the administration initially expressed the expectation that the new minister would work to resolve such pressing issues as a renegotiation of the bilateral agreement.

However, that portion about a renegotiation was subsequently deleted, apparently out of concern over the possible effect on relations with Japan.

Those close to the Moon administration have made clear that it wants to separate historical recognition issues from other matters concerning Japan.

One member of the delegation that visited Japan in May on behalf of the Moon administration said, "If we use such words as renegotiate or invalidate, Japan will not engage in dialogue. We have to think of a way to conduct discussions over a wide range of historical recognition issues."

Although the Moon administration has placed promotion of dialogue with its northern neighbor as its top foreign policy priority, Pyongyang's behavior remains unpredictable.