SEOUL (Reuters) - New video obtained by a South Korean broadcaster offers a glimpse of a daring defection by a North Korean man who last week swam, crawled through a tunnel, and wandered around the heavily guarded border zone for hours before being noticed. The man, who has not been identified by South Korean authorities, crossed the Demilitarized Zone (DMZ) from North Korea on Feb. 16, according to the South’s military. The grainy video footage, obtained by South Korean broadcaster TV Chosun, shows a dark figure passing under a road sign as bright lights flash. Wearing a diving suit and fins, the man had swum for around six hours in the ocean in the dead of night, coming ashore more than 3 km (1.9 miles) inside South Korean territory, the Joint Chiefs of Staff said this week in a report cataloguing a series of failures by border security troops. He then passed under a fence by climbing through a drainage tunnel that security forces had been unaware of, the report said. Despite triggering alarms and appearing on surveillance cameras multiple times, the man was not noticed until around three hours after he came ashore, the JCS said. It took troops several more hours to track him down and detain him. The delays in detecting the man drew fresh criticism of border security, after a similar publicly known case in November, when a North Korean man defected to the South via the eastern DMZ. Defections across the DMZ are rare, as the area is closely guarded by troops from both sides, and is strewn in many places with barbed wire, landmines, and other barriers. After North Korea closed its border with China last year to guard against a coronavirus outbreak, defections through the more usual routes have slowed to a trickle.