While North Korea has supplied weapons to Russia for some time, the arrival of troops is a major escalation of its involvement in the war in Ukraine.

The first official evidence that large numbers of North Korean troops entered Russia was provided by the South Korean government, which last week published a press release detailing the growing military cooperation between the two states.

According to the press release, an initial contingent of 1,500 North Korean special forces was transported on Russian warships to the port city of Vladivostok.

The South Koreans provided two high-resolution satellite images showing what they say are these troops in two locations in Russia.

The first shows a crowd of what the South Korean government estimates are 400 people gathered in an open space inside a Russian military site near the city of Ussuriysk, 98 kilometers north of Vladivostok.

The second picture shows a smaller number of people, which the South Korean government state is about 250 North Korean soldiers.

This photo was taken further north than the first. It shows an area that appears to be a military site near the city of Khabarovsk in the Russian Far East.

Movies circulating online

Amid reports of North Koreans entering Russia, several videos circulated widely.

Sky News cannot confirm they show North Korean troops, but one shows a group of East Asian-looking soldiers. The person filming the video states they are North Korean and refers to them as “allies”.

This video has been geolocated by Sky News to the town of Sergeyevka in the Russian Far East.

A second video filmed nearby shows a group of soldiers training in a field at the same location.

Filmed over a wall, the footage is too grainy for the soldiers to be visually identified, but many have claimed it shows North Korean troops.

A third video, released by the Ukrainian government, shows troops being equipped. Although it is not possible to geolocate this footage, the presence of boxes marked in Russian has been cited as evidence that this shows North Korean troops in Russia.

What satellite images can tell us

Although currently available videos do not tell a complete story, more can be learned from satellite images.

An image taken by Maxar of the site in Sergeyevka shows the sudden appearance of trenches on the foundation of the base in early October.

Later in the month, equipment can be seen assembled in an area in the southern part of the site, indicating that it has continued to be used. This coincides with the reported arrival of troops in the area and the appearance of the videos, and is consistent with reports that the North Koreans are training in the area.

Available satellite images appear to show that a nearby training ground in Lifarevka is also in use.

A comparison between low- and high-resolution images taken during the month of October shows that several huts appear to have been renovated at the site.

Training pits and signs of activity can be seen in high-resolution images taken on 24 October.

The fighting on the Ukrainian front lines often involves the use of trenches similar to those seen in both locations.

A North Korean flag appears on the front line

Amid reports that North Korean troops were being prepared for fighting in Ukraine, an image showing the North Korean flag next to that of Russia went viral.

Sky News has geolocated this to a former mining site between the towns of Hirnyk and Tsukuryn in eastern Ukraine.

The site is close to the front line, where Tsukuryn was captured by the Russians in early October.

While the presence of the North Korean flag does not necessarily signal their arrival in Ukraine, it does suggest that frontline Russian forces are aware of North Korea’s increasing involvement in the conflict.

Arms deliveries

North Korea’s support for the Russian war effort is not a new phenomenon.

In October 2023, the White House released images showing a Russian ship collecting containers of what the Americans claim were weapons from the North Korean port of Rason.

Before this time, the port of Rason had been largely empty. Sky News found there was little activity at its docks until late summer, after which an increasing number of ships were visible in the autumn and winter.

Between late August and mid-February, Sky News recorded 34 days during which vessels were visible at Rason’s once-empty docks.

While it is not publicly known how much weapons have been provided by North Korea, the White House claimed in February that 10,000 containers of ammunition and other military materials had been shipped since September 2023.

The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We collect, analyze and visualize data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling, we strive to better explain the world while showing how our journalism is done.