Emboldened by its security and economic alliance with Moscow and flush with cash after sending troops and military equipment to support Russia's invasion of Ukraine, North Korea is testing boundaries closer to home.

In a meeting in late June with the United Nations Command, South Korea's Defense Ministry expressed concern about activity by North Korean engineers at a number of locations along the length of the 238-kilometer-long (148 miles) Demilitarized Zone (DMZ), which has divided the Korean Peninsula since an armistice brought the 1950-53 Korean War to an uneasy conclusion.

There have been countless clashes and incursions over the DMZ in the decades since, with North Korean invasion tunnels detected deep underground, defectors risking their lives to cross minefields and barbed wire entanglements to reach freedom in the South, as well as the occasional exchange of gunfire.How North Korea uses Christianity to protect Kim dynastyTo view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video

Is North Korea pushing limits in the DMZ?

Choo Jae-woo, a professor of foreign policy at Kyung Hee University in Seoul, believes the North is now probing to see how far it can push before it meets resistance."They are testing the limits," he told DW. "They know they have the support of both Russia and China in all their endeavors — military, economic, geopolitical — and Pyongyang feels that now is the time to see how far it can go."