SEOUL (REUTERS) - A North Korean man who crossed the heavily fortified border with South Korea has said he wants to defect to the South, Seoul officials said on Thursday (Nov 5).

The man was taken into custody in the Demilitarised Zone separating the two Koreas on Wednesday, several hours after he was spotted crossing barbed wire fences installed along the border, prompting an urgent search operation.

Authorities have launched an investigation into how the man managed to cross the frontier, South Korea's Joint Chiefs of Staff (JCS) said.

"I understand the person has expressed his willingness to defect," JCS spokesman Kim Joon-rak told a briefing, declining to provide further detail during the ongoing investigation.

Mr Kim said border controls were being further examined after the search for the man revealed that some parts of the fences equipped with electronic monitoring systems were found to have been damaged, possibly by typhoons.

There was no unusual movement from North Korean troops, Mr Kim added.

The defection cames just as Seoul reopens tours to the southern part of the DMZ, which has seen several armed clashes but also served as a venue for key inter-Korean events, including some of the most recent summits.

The tours had been suspended in October 2019 after an outbreak of deadly African swine fever broke out in North Korea, and then due to concerns about the novel coronavirus this year.

This week's DMZ crossing is the first since a North Korean soldier defected to the South in 2019.

Another soldier crossed in 2018, and in a more dramatic 2017 incident, North Korean troops fired at a soldier when he drove an army truck through the DMZ.