Why is North Korea fortifying its border with South Korea?

A row over a landmine blast and a threat to resume loudspeaker broadcasts has highlighted Kim Jong-un’s military ambitions

Last week North Korea hit the headlines with a vow to fire up its loudspeaker systems to blare propaganda into the South, but the latest dispute comes against a backdrop of militarisation of the border by Kim Jong-un that has been years in the making.

Since April 2024, North Korea has been working on building a permanent fortified border through the demilitarised zone (DMZ) that divides the two sides, work that has led to a mine explosion that injured three South Korean soldiers and plunged ties to new lows.

Here’s a brief guide to what is being built, what Pyongyang says it’s for, and why even deciding where the border is has become such a fraught issue.