Image copyright Getty Images Image caption The border area is guarded by thousands of troops on both sides

South Korea has detained a North Korean soldier who crossed the heavily guarded demilitarised zone (DMZ) that divides the two Koreas.

He was detected by thermal imaging equipment overnight, said South Korea's Joint Chiefs of Staff (JSC).

The unidentified man was an active-duty soldier who expressed interest in defecting to Seoul, said the JCS.

Dozens of people escape North Korea every year but defections across the DMZ are extremely dangerous and rare.

In November 2017, a North Korean soldier was shot at 40 times by his fellow troops as he crossed the zone.

Media playback is unsupported on your device Media caption A rare instance of a defector fleeing through the demilitarised zone was captured on CCTV in 2017

In the latest incident, the man was first detected late at around midnight on Wednesday near the Imjin river, which flows from North Korea into South Korea across the DMZ on the west of the peninsula.

He was picked up by South Korean troops and taken into military custody.

The apparent defection comes a day after North Korea carried out two short-range missile launches.

North Korean state media KCNA said the launches, overseen by Kim Jong-un, were test firings of a "new-type large-calibre multiple launch guided rocket system".

The tests were a "warning" to South Korea over planned military exercises scheduled to take place with the US later this month, North Korea said.