National Security Adviser Shin Won-sik speaks during a press briefing held at the presidential office in Seoul, Sept. 1. Yonhap

National Security Adviser Shin Won-sik warned on Monday that North Korea retains the capability to conduct nuclear tests at any time, with one possible timeframe for their next test potentially aligning with the U.S. election in November.

Shin made the comment during a televised interview when asked about the timing of Pyongyang's potential seventh nuclear test.

He emphasized that South Korea and the U.S. are closely monitoring North Korea's nuclear activities as a "top priority."

"North Korea has always maintained the ability to conduct its seventh nuclear test whenever Kim Jong-un decides," Shin explained, noting that the regime likely needs this test to further develop nuclear miniaturization capabilities.

"The timing will depend on North Korea's strategic interests, and the period surrounding the U.S. election is one possible timeframe," he added.

S. Korea, US, Japan trilateral summit by year-end

The national security adviser also said that a trilateral summit between South Korea, the U.S., and Japan is expected to take place by the end of this year.

"As agreed at Camp David last year, the three countries are planning to hold the summit within this year. While discussions are still ongoing about whether the summit would occur during a multilateral event or as a separate meeting, what I can say for sure now is that it is highly likely to happen this year," Shin said during the televised interview.

He emphasized that the three countries share a common perspective on strengthening trilateral security and comprehensive cooperation, and this stance will "remain unchanged regardless of any political shifts or leadership changes."

Former Presidential Chief of Staff Lim Jong-seok walks out of a press briefing room at the National Assembly in Seoul, Feb. 28. Yonhap

Shin also criticized a recent proposal by Lim Jong-seok, the former Presidential Chief of Staff during the Moon Jae-in administration, to accept North Korea's "two-state theory."

"It is deeply regrettable, dangerous, and unconstitutional to suddenly align with North Korea's proposal," Shin said, emphasizing that despite North Korea's denial of the concept of a united nation, South Korea will continue to pursue peaceful unification based on the liberal democratic order enshrined in the Constitution.

He criticized previous administrations for staging what he described as "political shows" that seemed to promote peace but ultimately provided North Korea with time and space to advance its nuclear program. This, he said, worsened inter-Korean relations and security on the Korean Peninsula.

In contrast, the national security adviser stressed that the Yoon administration is pursuing a sincere and principle-based approach to North-South relations.

"We are always open to dialogue and maintain the position that any topic can be discussed. North Korea must realize that threats and provocations will never get them what they want. We hope they seize this opportunity to engage in genuine dialogue and seek a compromise, and we look forward to a sincere response to the proposals outlined in the unification doctrine announced on August 15," Shin said.

The front windshield of a vehicle is shattered by a balloon filled with suspected waste material from North Korea in Gyeonggi Province, June 2. Courtesy of Gyeonggi Nambu Provincial Police Agency.

Referring to a recent surge in North Korea's waste balloon launches toward South Korea, Shin called on the North to stop such "petty and low-level provocations."

Shin went on to assure the public that the government is implementing all necessary preventive measures as well as immediate countermeasures.

"The government will continue its approach of assessing potential safety risks once the balloons have landed and swiftly removing them. We believe this is the most effective response," Shin said during the interview.

Additionally, Shin highlighted that the South Korean military will display powerful strategic weapons capable of countering North Korean nuclear and WMD threats at the upcoming Armed Forces Day, which falls on October 1.