First reported deaths of North Korean soldiers fighting against Ukraine

Ukraine's military intelligence agency and the Pentagon said that some North Korean troops have been killed during combat against Ukrainian forces in Russia's Kursk border region.

These are the first reported casualties since the US and Ukraine announced that North Korea had sent 10,000 to 12,000 troops to Russia to help it in the almost three-year war.

Ukraine's military intelligence agency said around 30 North Korean troops were killed or wounded during battle with the Ukrainian army over the weekend.

The casualties occurred around three villages in Kursk, where Russia has for four months been trying to quash a Ukrainian incursion, the agency, known by its acronym GUR, said in a public post on the Telegram messaging app.

At least three North Korean servicemen went missing around another Kursk village, GUR said.

Major General Pat Ryder, Pentagon press secretary, told reporters that some North Korean troops have died in combat in Kursk but did not have a specific number of those killed or wounded. Those troops have primarily been used in an infantry role and started fighting in combat operations about a week ago, Ryder said.

Kremlin spokesman Dmitry Peskov referred questions to the Russian Defence Ministry, which didn't immediately comment.

North Korean leader Kim Jong Un has pledged unwavering support for Russia's full-scale invasion of its neighbour under a mutual defence pact.

The alliance gave a jolt to international relations, and Russian President Vladimir Putin said that the planned deployment of US intermediate-range missiles to Europe and Asia has brought new threats.

"In view of rising geopolitical tensions, we must take additional measures to ensure the security of Russia and our allies," Putin told a meeting with top military brass. "We are doing it accurately and in a balanced way to avoid being drawn into a full-scale arms race."

However, military analysts say the language barrier has bedeviled combat coordination between Russian and North Korean troops.

"The poor integration and ongoing communication problems between Russian and North Korean forces will likely continue to cause friction in Russian military operations in Kursk … in the near term," the Institute for the Study of War, a Washington think tank, said.

On November 5, Ukrainian officials said their forces had for the first time engaged with North Korean units that had been recently deployed to help Russia.

Ukraine seized land in Russia's Kursk border region last August in what was the first occupation of Russian territory since World War II. The operation embarrassed the Kremlin and aimed to counter unceasingly glum news from the front line.

The incursion hasn't significantly changed the war's dynamics. Over the past year, Russia has been on the front foot, with the exception of Kursk, and has been grinding deeper into eastern Ukraine's Donetsk region despite heavy losses.

Russian Defence Minister Andrei Belousov said the military has been making steady gains in Ukraine, claiming that they have accelerated recently, with Russian forces capturing about 30 square kilometres of territory a day.