Seoul’s military said a small boat carrying suspected North Korean defectors was detained after crossing into the South’s waters.

There was a detection on South Korea’s side of the Northern Limit Line, the maritime boundary between the two countries.

In a statement, the Joint Chiefs of Staff said the four people on board were “presumed to have defected” from North Korea.

Since North Korean leader Kim Jong Un took power in 2011, border controls have also been tightened more since the Covid-19 pandemic of 2020.

Further details about the four North Koreans on board the wooden boat were not released by the South Korean authorities.

Nine North Koreans were rescued by the coast guard in May after crossing the western sea boundary aboard a fishing boat.

It is common for defectors to be detained and questioned for up to a month, in order to determine their motivations for leaving.

As part of their preparation for life in South Korea, they are sent to Hanawon, a resettlement center.

A “large number” of North Korean defectors were forcibly repatriated by Beijing earlier this month, Seoul announced. According to human rights groups, 600 North Koreans have been sent back, and they face imprisonment, sexual violence, or even death in the North.

North Korean defectors are not recognized as refugees by China. Despite requests from foreign governments and human rights groups, it calls them “economic migrants” and sends them back.