Tensions on the Korean Peninsulas are at their highest point in years, with the pace of both Kim’s weapons tests and combined military exercises between the United States, South Korea and Japan intensifying in a cycle of tit-for-tat.

The Koreas have engaged in a Cold War-style psychological warfare which has seen North Korea drop tonnes of rubbish on the South with balloons and the South broadcasting anti-Korean propaganda with its loudspeakers.

South Korea’s military said soldiers fired warning shots to repel North Korean soldiers who temporarily crossed the rivals’ land border on Tuesday for the second time this month.

The South’s military said North Korean has been increasing building activity in frontline border areas, such as installing suspected anti-tank barriers, reinforcing roads and planting land mines.

Lim Soosuk, spokesperson of South Korea’s Foreign Ministry, said Seoul has been stressing to Moscow any cooperation between Russia and North Korea must not proceed in a direction which violates UN Security Council resolutions or undermines peace and stability in the region.