Seoul will raise security levels to Red, the highest, at the Incheon, Gimpo, Gimhae, Cheongju, and Jeju airports from Monday, three days before the Group of 20 summit opens in Seoul.

The Ministry of Land, Transportation, and Maritime Affairs said Sunday that this is the first time security levels at major airports in South Korea has been raised to Red.

There are five levels to airport security: Green-Blue-Yellow-Orange-Red, depending on contingencies in national airport security.

Security level is raised to Red with suspicion of terrorism or with certain risk towards airlines or airplane facilities.

A ministry official said the security level will be raised to prevent acts of terrorism on key political figures, as major foreign officials are to visit Korea earlier next week.