SEOUL, Aug 8, 2024 (BSS/AFP) - A North Korean has defected to the South across a de facto maritime border in the Yellow Sea, Seoul's military said Thursday.

Tens of thousands of North Koreans have fled to South Korea since the peninsula was divided by war in the 1950s.

The latest defection comes as relations between the two Koreas are at one of their lowest points in years, with the North ramping up weapons testing and bombarding the South with trash-carrying balloons.

"The South Korean military has secured a suspected North Korean individual and handed them over to the relevant authorities", Seoul's Joint Chiefs of Staff said, adding there has been no unusual movement by the North Korean military detected.

"Relevant authorities are currently investigating the exact process of the defection and whether the individual wishes to defect to the South," it added.

The individual arrived "on foot" early Thursday on Gyodong island, off the peninsula's west coast near the border between the Koreas, and "two defectors had been initially spotted, raising the possibility that one of them may have failed to cross", the Yonhap news agency reported, citing unnamed military sources.

Other South Korean media reported Thursday that two North Koreans attempted to defect to the South through the border island, less than five kilometres (3.1 miles) from North Korea.

Most defectors go overland to neighbouring China first, then enter a third country such as Thailand before finally making it to the South.

The number of successful escapes dropped significantly from 2020 after the North sealed its borders -- purportedly with shoot-on-sight orders along the land frontier with China -- to prevent the spread of Covid-19.

But the number of defectors making it to the South almost tripled last year to 196, Seoul said in January, with more elite diplomats and students seeking to escape, up from 67 in 2022.

-- 'Unhappy with the North's system' --

South Korean Defense Minister Shin Won-sik told a parliamentary committee that an investigation was "underway by the relevant authorities".

Shin said it was a "successful mission" which the South's military "continued to monitor and guide" from the individual's point of departure.

The incident is the first time in 15 months that a North Korean defected to South Korea through the Yellow Sea.

In May 2023, a family of nine escaped the North using a wooden boat.

Experts say defectors have likely been impacted by harsh living conditions, including food shortages and inadequate responses to natural disasters, while living in the isolated North.

"North Korea has suffered severe flood damage recently and has caused a lot of damage in other areas as well, including parts of the city," Cheong Seong-chang, director of the Korean peninsula strategy at Sejong Institute, told AFP.

"It is possible that the people who were unhappy with the North Korean system may have used this internal instability and confusion to defect."

Heavy rainfall hit the North's northern regions in late July, with South Korean media reporting a possible death toll of up to 1,500 people.

Pyongyang treats defections as a serious crime and is believed to hand harsh punishments to transgressors, their families and even people tangentially linked to the incident.

South Korea has responded to the North's increased weapons testing and trash-carrying balloon bombardments this year by resuming propaganda broadcasts along the border, suspending a tension-reducing military deal and restarting live-fire drills near the border.

Ahn Chan-il, a defector-turned-researcher who runs the World Institute for North Korea Studies, said he believed Thursday's defection could be a sign that the South's broadcasts denouncing the North were having their desired effect.

"Given the anti-Pyongyang leaflets distributed by South Korean activists and the loudspeaker broadcasts, it is possible that these developments have stirred emotions among North Koreans and triggered impulses to defect," he told AFP.

The broadcasts -- a tactic which dates back to the Korean War -- infuriate Pyongyang, which previously threatened artillery strikes against Seoul's loudspeaker units.