The president and first lady will receive new passports. Online passenger list

Passenger list available

The leak was reported by KBS on Monday. As revealed by the broadcaster, the file titled "Passenger List (Republic of Korea-Belgium)" was published online in early June and was available for months.

It contained the names, positions, dates of birth and detailed passport details of the participants of the delegation traveling to Belgium, Italy and France in June. The list, apart from the head of state and the first lady, included office employees, diplomats, security guards and journalists.

"We take this matter very seriously and are conducting an in-depth investigation from various perspectives, including the circumstances of the leak," said a representative of the Ministry of Foreign Affairs, quoted by the Yonhap agency.

As The Korea Times reported on Tuesday, the Ministry of Foreign Affairs has already taken steps to issue new travel documents to all those affected.

They are betting on data leakage

South Korean authorities are currently treating the incident as a data leak, not a hacking incident. There is speculation in the media that third parties may have been involved in the matter, but investigators have not yet determined the exact circumstances of the leak or identified the people responsible.

As part of the investigation, a technical inspection of computers and e-mail accounts used during preparations for the June visit is being carried out.