A group of North Koreans recently arrived in a boat across the inter-Korean border, Seoul announced Thursday in what may be a rare maritime defection in the heavily patrolled Yellow Sea.

The unification ministry said the event occurred recently but declined to provide further details to NK News.

“A joint investigation by the relevant South Korean agencies is currently underway, such as whether [the North Koreans] intend to defect to South Korea,” the ministry told NK News. It is “difficult to confirm” specific details at this time, it added.

The government’s acknowledgment of a rare arrival from across