South Korea has said that in return for sending thousands of troops to assist Russia in fighting Ukraine, North Korea has received missiles from Moscow, along with other defense equipment.

South Korea’s national security adviser Shin Won-sik was asked by a reporter Friday what Pyongyang stands to gain from deploying an estimated 10,000 troops to Russia, to which he responded: "It is understood that North Korea has been provided with related equipment and anti-aircraft missiles to strengthen Pyongyang's weak air defense system."

Central Pyongyang, via Reuters

This appears based on the defense pact signed between Russian President Vladimir Putin and Kim Jong Un this summer. It requires both nations to provide military assistance to the other "without delay" if their territory comes under attack.

North Korean troops are reported to already be dispatched to Kursk region to assist Russian forces in repelling the Ukrainian cross-border offensive which stretches back to early August.

South Korea’s National Intelligence Service has briefed lawmakers this week, describing that DPRK troops in Russia were likely attached to an airborne brigade and marine unit. Intelligence officials have further alleged that the north has transferred 3,000 containers of artillery, missiles and other arms to Moscow throughout the Ukraine conflict. Russian oil has also been transferred. 

A new, Friday BBC report says both countries are also colluding to break US-led sanctions:

Russia is estimated to have supplied North Korea with more than a million barrels of oil since March this year, according to satellite imagery analysis from the Open Source Centre, a non-profit research group based in the UK.

The oil is payment for the weapons and troops Pyongyang has sent Moscow to fuel its war in Ukraine, leading experts and UK Foreign Secretary, David Lammy, have told the BBC.

North Korea is barred from UN and Western sanctions from buying oil on the open market. New satellite images purport to show sanctions-busting in progress with the help of Moscow:

The satellite images, shared exclusively with the BBC, show more than a dozen different North Korean oil tankers arriving at an oil terminal in Russia’s Far East a total of 43 times over the past eight months.

Further pictures, taken of the ships at sea, appear to show the tankers arriving empty, and leaving almost full.

BBC/Planet Labs images:

The US and UK governments have meanwhile cited the North Korean troop presence in Russia and Ukraine as justification for authorizing Kiev's attacks on Russian territory using long-range missiles. Putin has in turn blamed the West and this policy in particular for turning the conflict into a "global" one.