President Yoon Suk Yeol’s first deputy national security adviser has played down the significance of the recent leak of highly classified US intelligence documents involving South Korea, shortly before boarding a plane to the US to discuss a Seoul-Washington summit scheduled for late April.

Kim Tae-hyo, the adviser, told reporters Tuesday at Incheon International Airport that most of the information released online “was altered” and that this conclusion is shared by both Korean and US authorities. The Korean and US defense chiefs had discussed the issue over phone, Kim noted, stressing the disclosure would hardly affect the April meeting.

Since Friday, US officials have been tracing the source of the leak whose breadth of topics ranges from the war in Ukraine to China -- a widespread breach that appears to include intelligence on internal matters in countries including Korea, one of its biggest Asian allies.

Some of the leaked documents suggest Washington could have been spying on Seoul as they show senior Korean officials discussing US pressure to provide weapons to Ukraine despite their policy against it. Spying on allies is not uncommon, but the fact that it potentially involved senior officials and came ahead of the summit held to mark ties was troubling.

But Kim’s open remarks are a clear sign that Korean policymakers have decided not to read anything more into the release for now, as they prepare for Yoon’s state visit in April. The aim is to not only mark 70 years of South Korea-US relations, but display the kind of show of force strong enough to curb North Korea’s increasingly feisty rhetoric

The North has warned that nuclear attacks are a reality if the South and US continue their regular military drills. The latest weapons tested by the isolated country facing international sanctions over its nuclear and missile programs are now capable of delivering nuclear strikes “anytime and anywhere,” according to Pyongyang.

The five-day US trip by Yoon’s adviser, which started Tuesday, is expected to make Washington more committed to its pledge to explore all options including nuclear weapons to deter and respond to attacks on its allies. The strategy, known as “extended deterrence,” is what Seoul believes is the best course of action for a country that cannot seek an independent nuclear buildup, because of an international treaty banning it.

But Kim declined to add any details on the defense strategy before flying off to the US, saying it was too early to unveil any ongoing discussions on the topic. When asked to disclose other preparations he could make public, Kim offered no further explanation, citing protocol not to reveal anything concrete ahead of the gathering.

On Friday, Yoon essentially fired the top national security adviser for failing to update him on the latest summit preparations. Yoon’s office has not elaborated on the adviser’s “resignation.” The reshuffle was the latest evidence of discord within the administration over deciding on a to-do list at the summit.