An annual international security forum hosted by South Korea's defense ministry kicked off in Seoul on Tuesday for discussions on North Korea's denuclearization, cyberthreats, space security and other challenges.

The three-day vice-ministerial Seoul Defense Dialogue (SDD) got under way at Lotte Hotel in central Seoul under the theme of "How to Address Complex Security Challenges: Fostering International Solidarity."

The first fully in-person SDD session since 2019 brought together senior defense officials and civilian experts from 54 countries, the United Nations, European Union and North Atlantic Treaty Organization.

On the first day of the forum, the Space Security Working Group was launched as a new SDD gathering to discuss global cooperation in promoting security in the strategically crucial domain, according to the ministry.

The Cyber Working Group (CWG) was set to convene later in the day on the largest scale since its launch in 2017. This year's gathering of the CWG, part of the SDD, involved officials from 43 countries, NATO and the UN

On the margins of the SDD, Seoul's Vice Defense Minister Shin Beom-chul plans to host a meeting with his counterparts from the Association of Southeast Asian Nations to discuss mid- and long-term plans for bilateral defense cooperation.

On Wednesday, Shin is set to hold a series of meetings with three Asia-Pacific partner countries, Australia, New Zealand and Japan, to discuss cooperation in maintaining solidarity in the protection of "values and norms," according to the ministry.

The opening ceremony of the forum is scheduled for Wednesday morning. South Korean Defense Minister Lee Jong-sup will deliver opening remarks, while National Security Adviser Kim Sung-han and the Netherlands' Defense Minister Kajsa Ollongren plan to make keynote addresses.

The forum includes three key plenary sessions on cooperation in promoting North Korea's denuclearization and rebuilding trust within the Indo-Pacific region, and the role of the military in hybrid warfare involving both conventional and unconventional war instruments.

In addition, four special sessions have been arranged to discuss international peacekeeping operations, the fight against disinformation, defense technologies for military modernization and defense acquisition efforts.

Key sessions are to be livestreamed on YouTube. (Yonhap)