Lee Jo-eun of VOA's Korean Service contributed to this report.
WASHINGTON — Growing trade tensions between Seoul and Tokyo could undermine regional stability and complicate U.S. efforts to make progress on denuclearization with North Korea, said experts.
The tension between the two countries, with origins in Japan's pre-World War II occupation of Korea, has become an "unprecedented emergency," said South Korean President Moon Jae-in in a Wednesday meeting with executives of South Korea's top 30 conglomerates. "We can't rule out the possibility that the situation would be prolonged, despite our diplomatic efforts to resolve the issue."
The meeting took place in response to Japanese Prime Minister Shinzo Abe imposing tight export controls on three Japanese-made high-tech materials to South Korea. The materials restricted July 4 are used in the production of memory chips, TVs and smartphones.
Working level talks between South Korea and Japan are scheduled to begin Friday in Tokyo, according to South Korea's trade ministry. The talks come after Moon this week urged Japan to roll back the export restriction, saying he wants to resolve the dispute diplomatically.
The restriction comes in the form of a Japanese government review of sales of fluorinated polyamides, photoresists, and hydrogen fluoride to South Korea, which Tokyo plans to remove from its "white list" of national security allies that can receive sensitive Japanese exports without a permit. For example, hydrogen fluoride used as etching gas in chipmaking also can be used in chemical weapons.
Daniel Sneider, a Japan-Korea relations expert at Stanford University, said, "If you have a really serious breakdown of relations between Japan and South Korea, it has a real impact on the ability of the United States to fulfill its national security obligations in the region."
He continued, "The United States military relationship with Japan and the (military) base structure in Japan are an essential part of the defense of the Korean Peninsula. So to the extent to which our two allies are not cooperating with each other, including very important day-to-day cooperation, it undermines our security deterrence for South Korea."
The U.S. nuclear umbrella in the East Asia protects both Japan and South Korea, and the U.S. has military bases both in South Korea and Japan.
The tensions also touch on denuclearization of the Korean Peninsula.
Evans Revere, acting assistant secretary of state for East Asian and Pacific Affairs during the George W. Bush administration, said, "One rarely mentioned reason for the current level of Japan-Korea tensions is that Tokyo does not believe that South Korea is as dedicated to the cause of denuclearization as Japan is, and that (South Korea) may be prepared to tolerate a nuclear-armed North Korea, while Japan will never accept this."
Japan is the only country that has experienced a nuclear attack. Days before the end of World War II, the U.S. dropped nuclear bombs on Hiroshima and Nagasaki.
"It is widely believed among Japanese experts and officials that Seoul prioritizes reconciliation over denuclearization, a view that is also shared by many American experts," Revere added.
With Japan, the U.S. has a missile defense treaty and joint missile defense system to deter North Korea's nuclear threats in the region. The U.S. is also obligated to defend Seoul under a security treaty it entered with South Korea at the end of the Korean War.
On Tuesday, North Korea denounced Japan's plan to set up the U.S.-developed Aegis Ashore missile defense system in the country. Pyongyang called the defense system a "malignant cancer" and "overseas aggression" that can target not only the Korean Peninsula but also China and Russia.
Tokyo said the purpose of the Aegis Ashore deployment is to defend against possible North Korean ballistic missiles aimed at Japan.
The South Korean defense ministry said Thursday that it is against the U.N. Command's push to include Japan as an official member of the U.N. Command in South Korea. The U.N. Command in Korea on Thursday denied the report.
The U.S. leads the 16 countries in the U.N. Command in South Korea that can send troops and war supplies and support if war breaks on the Korean Peninsula. The multilateral military force was established during the Korean War to fight against North Korea and has been stationed in South Korea since then.
Sneider said daily military cooperation between the two U.S. allies is essential to guard against North Korean threats.
"A lot of day-to-day (activities) that go on between South Korean military and Japanese military … are all being undermined by this from a security point of view," Sneider said.
U.S. Secretary of State Mike Pompeo stressed "the importance of U.S.-Japan-(South Korea) trilateral cooperation" in denuclearizing North Korea when he spoke with South Korean Foreign Minister Kang Kyung-wha by phone Wednesday, according to State Department spokesperson Morgan Ortagus.
Revere said, "The major concern for many Americans about the current Japan-South Korea dispute is that it is undermining trilateral solidarity in the effort to deal with North Korea."
He continued, "The evident erosion of Seoul-Tokyo cooperation, dialogue, and summitry has damaged the close policy synchronization that once characterized trilateral cooperation against North Korea. The ultimate beneficiary of this is North Korea."
Democratic Sen. Chris Coons of Delaware told VOA's Korean Service, "My hope is that this can be worked out in a responsible fashion between two sets of trusted allies."
Republican Sen. Ted Cruz of Texas said, "There are always delicate issues with allies at the end of the day. Both Japan and South Korea are and will remain close friends and close allies."
The current tensions grow in part from Korean anger at Japan for decades of colonization and occupation of Korea from 1910 until Japan's 1945 surrender to the U.S. to end World War II. During that period, many Japanese companies used Korean forced labor.
Compensation for the victims came in a 1965 bilateral treaty that normalized postwar relations between the two countries.
The treaty's terms came up short, according to Korean activists who argued Japan's payment of about $300 million failed to provide fair compensation to people conscripted to work in Japanese companies.
Japan contends the treaty settled the compensation issues. The treaty said all claims are "settled completely and finally."
However, after decades of court battles in South Korea and Japan, South Korea's top court ruled last year that while the 1965 treaty settled disputes between the two governments, former forced laborers could sue Japanese companies individually. Then, in two related rulings, the court ordered Japan's Nippon Steel & Sumitomo Metal Corp., and Mitsubishi Heavy Industries Ltd., to pay a combined total of 14 South Korea plaintiffs hundreds of thousands of dollars in compensation.
Seoul has asserted that the current Japanese export control move is a politically motivated economic retaliation for the South Korean Supreme Court ruling allowing individuals to sue. Japan's chief cabinet secretary, Yoshihide Suga, referenced the court ruling in a press conference after the export curbs were announced last week, but denied the two issues were linked.
Mitsubishi faces a July 15 deadline to respond to a formal request for talks with Korean former forced laborers, according to Jiji News, and Japan has set a July 18 deadline for South Korea to meet its demand for a third-party arbitrator in the forced-labor dispute.
Tokyo also claims the export controls are in part a response to Seoul's violation of international sanctions imposed on North Korea.
Last August, Seoul announced that South Korean companies had illegally imported North Korean coal in violation of international sanctions on Pyongyang, and on Sunday, Abe told Japanese media that Seoul could be cheating on North Korea sanctions.
Abe said, just as "Seoul is not abiding by international commitments on the wartime labor issue," it is likely "not regulating trade" in compliance with North Korea sanctions.
Last week, South Korea released two of its ships that were impounded for carrying out ship-to-ship transfers to North Korean vessels in 2017 and 2918, in apparent violation of sanctions. The U.N. approved the release of the ships because, according to the South Korean foreign ministry, the ships did not deliberately breach the sanctions.