Kim Jong Un calls Russia's war sacred and pledges invariable support

North Korean leader Kim Jong Un told Vladimir Putin he would "expand and deepen" joint work with Russia and pledged "invariable support" for Putin and the Russian people, the Korean Central News Agency reported on 15 September.

The letter was a reply, sent on 14 September, to Putin's congratulations on the 78th anniversary of the Democratic People's Republic of Korea, which fell on 9 September. Kim wrote that Pyongyang's will was "firm without doubt" to broaden cooperation "in a comprehensive way" on the basis of friendship, mutual aid and what he called the two countries' alliance relations.

He added that he was "firmly convincing the victory of the Russian Federation in the present sacred war for defending the security interests of the country and international justice." KCNA and independent wires treated that phrase as a reference to Russia's war in Ukraine.

What "joint work" already means

Kim did not list projects. The record of the past two years fills in the phrase. North Korea and Russia signed a comprehensive strategic partnership treaty during Putin's visit to Pyongyang in June 2024. The text commits each side to military assistance "without delay" if the other is attacked.

Pyongyang has sent troops and conventional munitions to Russian units fighting in Ukraine. South Korea's intelligence service earlier estimated about 2,000 North Korean soldiers killed. A later assessment put killed and wounded together near 6,000. Those figures have not been confirmed by Pyongyang or Moscow and should be read as partner-service estimates, not battlefield accounting.

In return, analysts who track the relationship say North Korea has received fuel, cash and access to Russian military technology. The new letter does not confirm a fresh deployment. It does remove any ambiguity about how Kim wants the war described in official language: a sacred defence of Russian security and of "international justice."

A matching note to Beijing

Two days earlier KCNA published Kim's reply to Chinese President Xi Jinping on the same founding anniversary. That letter promised to develop the traditional friendship and to advance what Kim called their shared socialist cause. It did not use the "sacred war" formula.

The pairing is the point. Founding-day correspondence is ritual. Kim used the Russian channel to bless the war and the Chinese channel to keep the older alliance vocabulary intact. He can send both letters in the same week because neither capital is asking him to choose in public.

Why the wording matters this week

The letter landed as US President Donald Trump claimed Ukraine and Russia had agreed not to strike energy targets, a claim Kyiv treated as an American proposal rather than a signed halt. It also landed after a Russian drone wrecked a locomotive at Yahodyn, two kilometres from Poland, on a line that had just carried European officials.

None of that is in Kim's text. What is in the text is a decision to keep the 2024 treaty politically warm at a moment when other capitals are talking about pauses and guardrails. "Invariable support" is not a troop number. It is a refusal to treat the war as a subject on which Pyongyang might later hedge.

Japan's lower house speaker, Eisuke Mori, arrived in Kyiv on 14 September for the first visit by a Japanese House speaker since the 2022 invasion. He is due to address Ukraine's parliament on 15 September. The two events sit on the same date by coincidence. They describe the same alignment from opposite ends: one letter blessing the Russian campaign, one parliamentary visit restating Japan's rejection of a change of borders by force.

Kim's letter will not move a front line. It tells Russian and North Korean audiences that the alliance language of 2024 is still the official line in September 2026.