It is also possible that Mr Kim may be able to call in Russian weapons in the future.

The most worrying request Mr Kim could make is for Mr Putin to provide him with advanced weapons technology or knowledge to help him make breakthroughs with his nuclear weapons programme. Despite his efforts, he still struggles to master key strategic weapons, such as spy satellites and nuclear submarines.

However, Seoul officials believe cooperation on this level is unlikely, since it could end up being strategically harmful to Russia.

Yang Uk, a research fellow at the Asian Institute for Policy Studies, pointed out that Russia could still support North Korea’s nuclear program even if it does not sell weapons. North Korea’s weapons system can be strengthened if Russia pays in oil and food. This would be an extra source of income for them that they did not have before.”

“For 15 years, we have developed a network of sanctions against North Korea, to prevent it from developing and trading weapons of mass destruction,” Yang, a military strategist and weapons systems expert, said. As a permanent member of the UN Security Council, Russia could bring this system to a halt.”

As sanctions have been stepped up, North Korea has become increasingly reliant on China for food aid and to turn a blind eye to those who violate sanctions. In the past year, Beijing has refused to punish North Korea for its weapons tests at the UN Security Council, allowing it to develop its nuclear arsenal without serious consequences.

Beijing benefits from Pyongyang’s buffer zone between itself and US forces in South Korea.