Amid Furor, Seoul Downplays Leaked Pentagon Documents

SEOUL — South Korea downplayed on Tuesday the trove of highly classified Pentagon documents leaked through social media as the government of President Yoon Suk Yeol tried to deal with the fallout of what opposition lawmakers called a major security breach and possible violation of national sovereignty.

The leaked documents suggest that the United States has ​been spying on top national security officials in Mr. Yoon’s administration. Opposition lawmakers​ in Seoul accused Washington of “violating the sovereignty” of a key ally, calling the spying “a super-scale security breach​.”

“If it is true that they have spied on us, it is a very disappointing act that undermines the South Korea-U.S. alliance, which is based on mutual trust,” Lee Jae-myung, leader of the main opposition Democratic Party, told foreign media reporters on Tuesday. If it was true, he added, Washington should also apologize to the South Korean people.

Mr. Yoon’s administration has insisted that the scandal would not and should not damage his country’s alliance with the United States.​ On Tuesday, ​his government appeared to minimize the leak, saying that Defense Minister Lee Jong-sup and ​and his American counterpart, Defense Secretary Lloyd J. Austin III, had agreed during a Tuesday morning phone call that “quite a few of the documents in question were fabricated.”

But South Korean officials would not discuss the ​information contained in the leaked documents or what exactly they considered to be fabricated. So far, the leaked documents obtained by The New York Times have contained three​ entries on South Korea.

One document said that the South Korean National Security Council in early March was grappling with a request from the United States to provide artillery ammunition to Ukraine. Seoul has never​ confirmed such a request, although it said it was discussing selling 155-mm artillery shells to Washington on the condition that the U.S. military would be their “end user.” That stance was designed in part to prevent provoking Moscow, whose cooperation Seoul needs to contain an increasingly belligerent North Korea.

Another document showed senior presidential aides ​in Seoul concerned that President Biden would call Mr. Yoon to pressure him to ship ammunition to Ukraine or that the artillery shells South Korea was selling to the United States might end up in the war-torn country despite export controls. The aides also discussed the possibility of selling 330,000 artillery shells to Poland, with Warsaw “being called the end user” yet sending the ammunition on to Ukraine anyway.

​When asked if the conversation captured in the documents was accurate, Kim Tae-hyo, a deputy national security adviser to Mr. Yoon, said “No” to reporters at the airport on Tuesday, according to the national news agency Yonhap. Mr. Kim was departing for Washington to prepare for Mr. Yoon’s summit with Mr. Biden on April 26.

Mr. Yoon’s office would not comment beyond Mr. Kim’s remark. In the wake of Russia’s invasion of Ukraine, Poland has emerged as the biggest buyer of South Korean weapons, agreeing to purchase multibillion dollars’ worth of South Korean tanks, howitzers, missiles and aircraft.

A third document showed what looked like a timetable for 330,000 artillery shells ​in South Korea ​being airlifted to Ukraine or shipped from the South Korean port of Jinhae to the German port of Nordenham. It was unclear whether the timetable described a shipment already underway or just planned. The origin of the shells could indicate that the U.S. military was diverting its own stockpiles held in South Korea ​to Ukraine or that it was buying shells from South Korea to help replenish its own stockpiles.

Senior U.S. officials said the Federal Bureau of Investigation was working to determine the source of the leaks. The officials acknowledged that the documents appear to be legitimate intelligence and operational briefs compiled by the Pentagon’s Joint Staff, using reports from the government’s intelligence community, but that at least one had been modified from the original at some later point. The apparent authenticity of the documents, however, is not an indication of their accuracy.

Mr. Yoon’s office insisted on Tuesday that it had a strong system in place to thwart attempts at spying on its officials. It accused opposition lawmakers of spreading “fake, negative suspicions” in order to gin up votes.

“This is a self-damaging act against national interest that under​mines the South Korea-U.S. alliance at a time of ceaseless provocations and nuclear threat from North Korea,” it said.

The documents also said that North Korea had conducted checks on March 1 to prepare for an ICBM test flight. (The North launched an ICBM on March 16.) Another document said that the record-breaking number of intercontinental ballistic missile-class launchers North Korea showed during a military parade in February​ were “most likely carrying nonoperational systems.”

“The North paraded these nonoperational systems to portray a larger, more capable missile force than it possesses and to mitigate the risk of damage to its real missiles,” it said. Independent analysts have long said that the missiles North Korea shows during its parades were likely imitations.

The leaked document added that North Korea would probably be unable to outfit all of the paraded ICBM launchers with operational missiles capable of striking the continental United States during the next year “because of testing hurdles and resource constraints.”