Democratic Party of Korea lawmakers on Monday urged President Yoon Suk Yeol to fire principal deputy national security adviser Kim Tae-hyo over his response to a recent US intelligence leak.

In a written request submitted to the presidential office, the party’s lawmakers accused Kim of failing to apply sufficient verification before concluding that the leaked Pentagon documents had been forged.

“The Yoon administration, which has consistently kept up its kowtowing diplomacy, passed on the opportunity to issue a protest to the US and brushed aside the concerns of possible spying on the presidential office,” they said in the request.

The opposition lawmakers argued that a member of the US Air National Guard being arrested by the FBI as a suspect in the intelligence leak showed that suspicions surrounding the leak of classified US intelligence documents “turned out to be true.”

“It’s unfathomable on what grounds the presidential office and the deputy national security adviser insisted that the leaked documents were forged,” they said. They claimed that Kim “sided with the US with a preposterous defense” that the circumstances so far revealed do not suggest the alleged eavesdropping was “ill-intended.”

The lawmakers, in the request, asked that the presidential office dismiss Kim immediately and apologize for “putting national interests second.”

“In light of the grave national security disaster, there needs to be a clear investigation into all the facts on US spying as well as accountability against national security officials in charge.”

They characterized the alleged spying as “a serious violation of national sovereignty on the US’ part,” and called for a commitment from the US to ensure there is no recurrence.

A Yoon official told reporters in a closed-door briefing the same day that letting go of the deputy national security adviser, as one of the authorities involved in the preparations of the president’s summit with US President Joe Biden next week, “would not be of benefit to us.”

Democratic Party lawmakers, also on Monday, pushed for a plenary session of the National Assembly intelligence committee to grill the state intelligence service over the latest allegations.

The Assembly intelligence committee’s Rep. Youn Kun-young -- a member of the Democratic Party -- accused the National Intelligence Service of “attempting to hide something.”

In a phone call with The Korea Herald on Sunday, Youn said that the NIS canceled appointments for an in-person briefing twice, which he said was “highly unusual.” He said that the NIS has not responded to his requests for a written response either on how aware the state intelligence service was of the US spying, among other topics.

“It just doesn’t make any sense -- the NIS is behaving like they are trying to keep something hidden. They can come to brief me about what they know so far,” he said.

The NIS declined to comment on Youn’s claims, saying it concerned operations of the intelligence services.

Youn, who was director of state affairs planning and the monitoring office for former President Moon Jae-in’s Cheong Wa Dae, said that the Yoon administration’s response so far was “unbecoming of an independent country with sovereignty.”

After returning from his visit to Washington ahead of the Yoon-Biden summit, the deputy national security adviser told reporters Saturday that US authorities “expressed regret” on multiple occasions and “offered a promise for the two countries to work more closely and build upon a relationship based on mutual trust.”

He added that there was also discussion on strengthening the intelligence alliance between South Korea and the US.

Youn saw that the expression of regret coming from the US meant an admission of the suspected spying on an ally, South Korea, had taken place.