Ko Jong Chol, vice chief of the North Korean People’s Army’s General Staff, noted that Tuesday’s warning shots coincided with the South Korea-US summertime military drills and accused Seoul of deliberately trying to raise tensions.

Shortly after Ko’s statement, South Korea’s Joint Chiefs of Staff confirmed it had fired warning shots on Tuesday afternoon at North Korean soldiers who briefly crossed the military demarcation line in the central border region while carrying out unspecified construction work.

The South’s military said the soldiers returned to North Korean territory without incident and that the North didn’t return fire.

In recent months, South Korea’s military has occasionally used loudspeaker warnings and fired warning shots to repel North Korean soldiers crossing the military demarcation line.

The incidents were largely seen as accidental as North Korean troops build anti-tank barriers, plant mines and carry out other work to reinforce border defences amid heightened tensions.

Ko said the North Korean soldiers were conducting a “barrier project to permanently block the southern border,” as part of broader efforts of “completely separating” the territory between the Koreas, when the South responded with an audio warning and warning shots.

Ko said the North had informed US forces in the South of their plans for the border work on June 25 and July 18 to prevent accidental clashes.

“As the commanding officer responsible for the southern border management and security, I strongly demand (the South) to immediately stop the dangerous provocation aimed to make the fortification project in the southern border necessary for defending our sovereignty an excuse for escalation of tension,” Ko said in a statement.

Animosity between the Koreas is running high now as North Korean leader Kim Jong Un continues to flaunt his military nuclear capabilities and align with Russia over President Vladimir Putin’s war on Ukraine.

Citing the expansion of South Korea-US military exercises and the hard-line policies of Seoul’s previous conservative government, Kim last year declared that North Korea was abandoning its long-standing goals of a peaceful unification between the Koreas and ordered the rewriting of the North’s constitution to mark the South as a permanent enemy.

Kim’s government has so far dismissed the diplomatic overtures by Seoul’s new liberal president, Lee Jae Myung, who said last week that Seoul would seek to restore a 2018 inter-Korean military agreement aimed at reducing border tensions, while urging Pyongyang to reciprocate by rebuilding trust and resuming dialogue.