Gunfire on the Korean border as Kim Jong-un's troops cross into DMZ

South Korean soldiers were forced to shoot at dozens of North Korean troops who crossed the border yesterday in an unsettling flurry of activity hours after Vladimir Putin left Pyongyang. The crossing - the third in just two weeks - prompted South Korean soldiers to blast warnings from loudspeakers, but the North Korean troops did not retreat until they came under fire.

The countries technically remain at war as the 1950-1953 conflict ended in an armistice, and the Demilitarised Zone (DMZ) dividing the peninsula is already one of the most heavily mined places on earth despite its name. But North Korea is moving to reinforce that, laying more landmines, reinforcing tactical roads and adding what appear to be anti-tank barriers, Seoul's military said.

A similar crossing incident earlier this week saw several North Korean soldiers sustain injuries when they accidentally stumbled upon landmines they had recently laid along the border as they retreated. The increase in tensions between Seoul and Pyongyang comes as the pariah state's leader Kim Jong Un this week signed a comprehensive partnership deal with Russian President Putin.

The pact included a mutual defence clause that means each country must come to the other's aid in the event of war. People have stepped across the demarcation line that separates the two Koreas before. But these incidents typically take place under very special circumstances, and usually at the border village of Panmunjom where US President Donald Trump famously stepped across the line with North Korean leader Kim Jong Un.

Outside of Panmunjom, much of the DMZ is wilderness and in some parts is only marked by a sign mounted on a stick or a slice of concrete surrounded by heavy foliage. Because overgrown trees and plants may have been obscuring the signs marking the demarcation line, Seoul says, the North Korean troops may have stepped over the line without knowing it. But the southern side of the land border is protected not only by thousands of soldiers, guns and mines, but also by a dense network of cameras, motion sensors and other high-tech surveillance equipment.

Any breaches are therefore detected extremely quickly, and will result in troops trying to cross facing warning shots from the South Korean sentries who are prepared to shoot to kill if their foes do not retreat. Although South Korean officials believe the three separate crossing incidents in the past two weeks were likely accidents, they took place amid a flurry of construction close to the border. Analysts believe this fortification and the laying of additional mines is to crack down on any attempts by North Koreans to defect, but also to signal to Seoul that there is no path to peace any time soon.

'North Korea's activities seem to be a measure to strengthen internal control, such as blocking North Korean troops and North Koreans from defecting to the South,' one JCS official said. Meanwhile, Koh Yu-hwan, North Korean studies emeritus professor at Dongguk University, said the fresh fortification 'has rather symbolic significance'. 'By laying mines, North Korea is demonstrating once again that, as per the instructions of the supreme leader (Kim Jong Un), there will be no reconciliation with the South,' he added. 'North Korea is not laying mines across the entire frontline, but rather in areas that are easily observable by the South. They are also blocking roads and railways that were previously areas of inter-Korean cooperation.'

During a period of warmer ties in 2018, the two Koreas removed landmines along a section of the heavily fortified border in a bid to ease military tensions - but this brief period of reconciliation did not last long. Recent weeks have seen a tit-for-tat standoff that has resulted in Cold War-style psychological warfare. Both sides have said they are no longer bound by a military agreement signed in 2018 to reduce tensions. North Koreans have been installing anti-tank barriers, reinforcing roads and planting land mines intermittently since April this year.

And the animosities may worsen as Kim continues to accelerate his nuclear weapons and missiles development and align with Putin in the face of their separate, escalating confrontations with Washington. On Thursday, South Korea's government condemned an agreement by Kim and Putin at their summit this week in which the two nations vowed to aid each other if attacked. South Korea summoned Russia's ambassador to Seoul today in protest at the defence deal signed by Putin and Kim in Pyongyang.

Seoul 'strongly urged Russia to immediately stop military cooperation with North Korea and comply with (UN) Security Council resolutions,' the foreign ministry said in a statement. Putin also said this week that Moscow did not rule out military and technical cooperation with the North, or even sending weapons - all of which would violate rafts of UN sanctions against Pyongyang. Seoul urged Russia to live up to its responsibilities as a permanent member of the Security Council, the foreign ministry said. 'Violating Security Council resolutions and supporting North Korea, will harm our security and inevitably have a negative impact on Korea-Russia relations,' first Vice Minister Kim Hong-kyun said, according to the statement.

North Korea has been under UN sanctions since 2006 over its banned nuclear programme. The measures were initially supported by Russia, but Putin said in Pyongyang that the sanctions should now be reviewed. Moscow and Pyongyang have been allies since North Korea's founding after World War II and have drawn even closer since Russia's invasion of Ukraine in 2022 isolated Putin on the global stage. Seoul, which is a major weapons exporter, said this week that it would 'reconsider' a longstanding policy that bars it from supplying arms directly to Ukraine, following the North's mutual defence agreement with Russia. Putin warned South Korea Thursday that this would be a 'big mistake'.

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