trade may be "economic opportunism" but the motivation for the vast majority of it is geopolitical.

"Russia is very worried about the isolation of North Korea and believes that makes the situation dangerous as the US is taking a confrontational approach," he told DW.

"Moscow's position is that pressure on the North has not worked and has in fact caused Pyongyang to react because it feels threatened," he said. "So instead of isolation, which is not working, Russia is proposing engagement."

The UN condemned North Korea's missile test and vowed new sanctions

New ferry route

The most recent example of this support for Pyongyang is the plan to open a ferry route between North Korea and the Russian Far East port of Vladivostok, although the proposal has been delayed by strong protests fromJapan.

In 2014, Russia announced that it was canceling $10 billion of North Korea's $11 billion in Soviet-era debt and that the remaining $1 billion would be invested back into the country. Russian investors also agreed to sink $25 billion into the North's dilapidated railway system, while more would go into basic infrastructure. The two governments also announced that Russia would rebuild the North's power grid, while the two countries would develop the ice-free port of Rason for exports of Russian coal.

In total, Russia planned to increase bilateral trade almost ten-fold to $1 billion by 2020, and that does not appear to have been hampered by more recent UN sanctions.

Guns, gold and gas: What UN sanctions target North Korea?

Coal and iron

In August 2017, the UN Security Council adopted a