This is reported by the BBC.
According to the publication, the DPRK is strengthening its border in the demilitarized zone with South Korea, a few days after the soldier ran across it.
US diplomats in turn in South Korea reported that North Korean workers were seen digging a trench in the demilitarized zone. In particular, a snapshot of the works being produced, the American diplomat Mark Knapper.
Let's note, recently there was a successful attempt to escape a soldier from the DPRK to South Korea. So, the government of South Korea awarded the military, who participated in the rescue of the defector.
As previously reported, "URA-Inform", North Korea for several days violated the agreement on the truce of 1953 during the pursuit of a runaway soldier. As noted, the violation occurred at a time when his border guards were trying to track down a soldier who got to South Korea via Panmunjom.