SEOUL, South Korea (AP) — South Korea's military says a North Korean soldier has crossed the border between rivals to defect to the South.

South Korea's Joint Chief of Staff said that military officials were investigating the North Korean solider who crossed the military demarcation line Thursday inside the 4-kilometer-wide (2.5-mile-wide) Demilitarized Zone that separates the countries.

The military provided no other details.

The Koreas have shared the world's most heavily fortified border since the end of the 1950-53 Korean War. The conflict ended with an armistice, not a peace treaty, leaving the Korean Peninsula in a technical state of war.