Seoul CNN  — 

A South Korean government worker was shot dead after crossing a maritime border into North Korea, Seoul said Thursday.

According to Lt. Gen. Ahn Young-ho, a top official with South Korea’s Joint Chiefs of Staff, a worker with the Ministry of Maritime Affairs and Fisheries went missing in waters 1.9 kilometers (1.2 miles) south of the Yeonpyeong Islands on September 21.

A Defense Ministry official told reporters that a vessel belonging to North Korea’s fishery organization first discovered the missing South Korean in the sea near the islands. The man was on a piece of flotsam large enough to support one person, was wearing a life jacket and was exhausted, the spokesman said.

The South Korean is thought to have being in the process of defecting to North Korea, and the Defense Ministry official said a member of the North Korean vessel’s crew, believed to be wearing a gas mask, listened to the man making a testimony to that effect.

Later, a North Korean patrol vessel opened fire on the attempted defector, who was killed. Following this, a soldier in a gas mask and hazard suit approached the body and burned it.

In a statement, the South Korean military said it “strongly condemns the North’s atrocities” and urged Pyongyang to provide an explanation and punish those responsible.

“In addition, we sternly warn that North Korea is responsible for the atrocities committed against our citizen,” the statement added.

According to Unification Ministry spokesman Yoh Sang-key, the incident “throws cold water on our consistent patience and effort for inter-Korean reconciliation and peace and it goes directly against our people’s yearning for peace on Korean Peninsula.”

Tensions have been rising between North and South Korea since communication between the two sides was cut off in June, when Pyongyang first closed and then blew up a joint liaison office in Kaesong, a city on the northern side of the border.

This photo provided by the North Korean government shows the explosion of an inter-Korean liaison office building in Kaesong, North Korea, Tuesday, June 16, 2020. South Korea says that North Korea has exploded the inter-Korean liaison office building just north of the tense Korean border. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. (Korean Central News Agency/Korea News Service via AP)
North Korea blows up liaison office used for talks with South
01:53 - Source: CNN

The deterioration in relations came after a years-long rapprochement led by South Korean President Moon Jae-in resulted in historic meetings between himself and North Korean leader Kim Jong Un, as well as summits between Kim and US President Donald Trump.

But those meetings ultimately did not deliver significant results for all sides, and North Korea has taken an increasingly strident tone towards its southern neighbor, a shift in stance that has come as Kim’s sister, Kim Yo Jong, moved into a more influential position in the North Korean regime.

A South Korean civilian was killed by the North in 2008, when a soldier shot a South Korean tourist at the Mt. Kumgang ski resort. In 2010, 46 South Korea sailors and two South Korean marines and two civilians were also killed by North Korea in separate incidents.

CNN’s James Griffiths and Joshua Berlinger contributed to this report.