BUSAN, South Korea—An official says a North Korean soldier has killed two of his officers and defected to South Korea across their heavily armed border.

A South Korean Defense Ministry official says the defection took place around noon Saturday across the western section of the Demilitarized Zone.

The official declined to be identified because interrogation was still under way.

Defections across the land border are rare. The last known defection across the border by a North Korean soldier occurred in 2008.