North and South Korea tensions rise as Pyongyang fortifies border

The risk of clashes between North and South Korea is growing, according to international relations experts in Seoul, as Pyongyang steps up fortifications along their heavily militarised border.

Tensions have been escalating in the area since three South Korean soldiers were injured in a landmine blast within the demilitarised zone (DMZ) last month.

North Korea has said it will resume propaganda broadcasts along the border and has also been adding mines, barbed wire fences, anti-tank barriers and other fortifications.

A visit from the North Korean leader's sister to the site this week prompted Pyongyang to renew its threat of retaliation against any South Korean provocation.

Kim Yo Jong said that if South Korean warning shots — which Seoul says are designed to force North Korean soldiers back across the border — caused "actual harm to our territorial security and our service persons' safety", North Korea "will show no mercy for the armed gangsters bereft of reason".

"Our tactical hunting teams are taking new positions, and within October, the loudspeakers for psychological warfare against the ROK will be in operation along the whole border," she said, using the initials of South Korea’s formal name, the Republic of Korea.

South Korea's defence ministry spokesperson Chung Binna said Seoul would need to take "proportionate measures" in response but did not elaborate on what that would involve.

South Korea’s Joint Chiefs of Staff chairman, Jin Yong-Sung, has ordered the military to "sternly respond" to potential provocations by the north.

Daniel Pinkston, an international relations lecturer at Troy University in Seoul, told the ABC North Korea had been moving towards this position for two and a half years after its leader Kim Jong Un announced the two Koreas would be "permanently divided as two enemy states".

"Koreans have lived in the shadow of this possibility [of border clashes] for decades now," he said.

"There have been patterns of increasing violence."

He told the ABC he visited a border observation post at the weekend and saw construction work being done but no sign of weapons.

Mr Pinkston said a lot of the area was mountainous and it was uncertain where the actual military demarcation line was, meaning one wrong step could be problematic.

“There’s always a possibility of airplane overflights or accidental incursions into airspace with this building of the fortifications," he told ABC's The World.

"There have been accidental or even deliberate crossings that have resulted in the military rhetoric and the threats to retaliate."

South Korea’s military has said North Korean soldiers crossed the border’s military demarcation line 50 times this year during fortification work, and that it responded with warning shots and broadcasts, a claim disputed by the north which said South Korean provocations had increased “beyond the red line” since the mine blasts.

Mr Pinkston said despite North Korea putting a lot of focus on its ballistic missile program and carrying out nuclear tests and nuclear weapons development, he said command and communications issues held them back from war.

“I don’t think they could win a conventional war, they’re at a disadvantage, but they have these asymmetric advantages in nuclear weapons and WMD (weapons of mass destruction)," he told the ABC.

Mr Pinkston said many South Koreans, including the president, wanted peace and reunification with the north but the north showed "no interest in dialogue".

He said North Korea's growing relationship with Russia, with Pyongyang sending many military personnel to help fight against Ukraine, could be giving Kim Jong Un more confidence to take stronger action against the south.

“These relationships with China and with Russia in particular could embolden Kim Jong Un," he said.