South Korea summons Russian ambassador as tensions rise with North Korea

South Korea summoned the Russian ambassador in protest at the country’s new defence pact with North Korea on Friday, as border tensions continued to rise, with vague threats and brief, seemingly accidental, incursions by North Korean troops.

Earlier on Friday, the powerful sister of North Korean leader Kim Jong Un issued a vague threat of retaliation after South Korean activists flew balloons carrying anti-Pyongyang propaganda leaflets across the border.

South Korea’s military said it had fired warning shots the previous day to repel North Korean soldiers who briefly crossed the rivals’ land border for the third time this month.

It came two days after Moscow and Pyongyang reached a pact vowing mutual defence assistance if either is attacked, and a day after Seoul responded by saying it would consider providing arms to Ukraine to fight Russia’s invasion.

Mr Zinoviev told Korean officials that any attempts to “threaten or blackmail” Russia were unacceptable and that his country’s agreement with North Korea wasn’t aimed at specific third countries, Russia’s embassy wrote on its X account. The South Korean ministry said Mr Zinoviev promised to convey Seoul’s concerns to his superiors in Moscow.

UN secretary-general Antonio Guterres warned Russia and cited UN Security Council sanctions against The Democratic People’s Republic of Korea, the country’s official name, which ban all countries from providing the DPRK with any material for nuclear or ballistic missile programmes.

“Any relationship that any country has with DPRK, including the Russian Federation, must entirely abide by those sanctions,” he told reporters at the UN headquarters in New York.

Leafletting campaigns by South Korean civilian activists in recent weeks have prompted a resumption of Cold War-style psychological warfare along the inter-Korean border.

The South Korean civilian activists, led by North Korean defector Park Sang-hak, said it sent 20 balloons carrying 300,000 propaganda leaflets, 5,000 USB sticks with South Korean pop songs and TV dramas, and 3,000 US dollar bills from the South Korean border town of Paju on Thursday.

Pyongyang resents such material and fears it could demoralise frontline troops and residents and eventually weaken Kim Jong Un’s grip on power, analysts say.

In a statement carried by North Korea’s official Korean Central News Agency, Kim Yo Jong, who is also one of her brother’s top foreign policy officials, called the activists “defector scum” and issued what appeared to be a threat of retaliation.

After previous leafletting by South Korean activists, North Korea launched more than 1,000 balloons that dropped tons of rubbish in South Korea, smashing roof tiles and windows and causing other property damage.

Kim Yo Jong previously hinted that balloons could become the North’s standard response to leafletting, saying that the North would respond by “scattering dozens of times more rubbish than is being scattered on us”.

In response, South Korea resumed anti-North Korea propaganda broadcasts with military loudspeakers installed at the border for the first time in years, to which Kim Yo Jong, in another state media statement, warned that Seoul was “creating a prelude to a very dangerous situation”.

Tensions between the Koreas are at their highest in years as Kim Jong Un accelerates his nuclear weapons and missile development and attempts to strengthen his regional footing by aligning with Mr Putin in a standoff against the US-led West.

Seoul has already provided humanitarian aid and other support while joining US-led economic sanctions against Moscow. But it has not directly provided arms, citing a long-standing policy of not supplying weapons to countries actively engaged in conflict.

Mr Putin told reporters in Hanoi, Vietnam, on Thursday that supplying weapons to Ukraine would be “a very big mistake”, and said South Korea “shouldn’t worry” about the agreement if it is not planning aggression against Pyongyang.

North Korea is extremely sensitive to criticism of Mr Kim’s authoritarian rule and efforts to reach its people with foreign news and other media.

In 2015, when South Korea restarted loudspeaker broadcasts for the first time in 11 years, North Korea fired artillery rounds across the border, prompting South Korea to return fire, according to South Korean officials. No casualties were reported.

In the latest border incident, South Korea’s joint chiefs of staff said several North Korean soldiers engaged in unspecified construction work briefly crossed the military demarcation line that divides the two countries at about 11am on Thursday.

The South Korean military broadcast a warning and fired warning shots, after which the North Korean soldiers retreated.

South Korea’s military says believes recent border intrusions were not intentional, as the North Korean soldiers have not returned fire and retreated after the warning shots.

The South’s military has observed the North deploying large numbers of soldiers in frontline areas to build suspected anti-tank barriers, reinforce roads and plant mines in an apparent attempt to fortify their side of the border.

Seoul believes the efforts are likely aimed at preventing North Korean civilians and soldiers from escaping to the South.