South Korea on Tuesday said its soldiers fired warning shots after North Korean soldiers briefly crossed the heavily fortified border separating the two rival neighbors.

South Korea's Joint Chiefs of Staff (JCS) said that around 20 to 30 North Korean soldiers, who had been engaged in unspecified construction work on the northern side, briefly crossed the demarcated border at 8:30 a.m. (2330 GMT/UTC).

The JCS said the North Korean soldiers returned to their side of the border after South Korean border patrols fired warning shots.
A similar incident occurred on June 11 after another group of North Korean soldiers briefly crossed the border.

Landmine explosions injuring North Korean troops

South Korea's military also said that landmine explosions near the border injured several North Korean soldiers, adding that Pyongyang had recently deployed troops to clear scrub and lay mines amid worsening relations between the two neighbors.

The JCS said it anticipates Pyongyang will increase its border construction activities, which it said could be aimed at making it more difficult for North Korean civilians or soldiers to escape to the South.

Worsening relations

When relations had not been as frosty in 2018, the two Koreas removed landmines along a section of the fortified border in a move to ease military tensions. 

Pyongyang has been sending thousands of trash-filled balloons south which it says is a response to balloons carrying anti-Pyongyang propaganda sent north by activists.

In response to the trash balloons, the South Korean government earlier this month also suspended a 2018 tension-reducing military deal and restarted loudspeaker propaganda broadcasts along the border.

The move irked Pyongyang, which warned Seoul was creating "a new crisis."

The neighbors remain technically at war as the 1950-1953 conflict ended in an armistice rather than a peace treaty.

The demilitarized zone and line of control dividing the peninsula is one of the most heavily mined places in the world.

Russian president heads to Pyongyang 

Amid these simmering tensions, Russian President Vladimir Putin is heading to Pyongyang on Tuesday for a summit with North Korean leader Kim Jong Un, in a sign of strengthening ties.

The US and its allies have accused North Korea of supplying Russia with arms, including ballistic missiles to use in its invasion of Ukraine.

Both countries are under multiple UN sanctions — Pyongyang since 2006 over its banned nuclear and ballistic missile programs and Moscow over the invasion of Ukraine.

kb/rc (dpa, AP, AFP)