It looks like Kim Jong Un and Vladimir Putin are becoming BFFs

SEOUL, South Korea — Is the sun setting on the brotherly bond between North Korea and its biggest patron, China?

North Koreans often compare the indefatigable relationship to “lips and teeth.”

China is North Korea’s biggest investor, and has long sustained the regime, with economic and political backing — even if that means bypassing United Nations sanctions and flouting international refugee law. Defectors fleeing across the Tumen or Yalu rivers to China are hunted down and repatriated, risking imprisonment and torture back home.

But in recent years, China has become weary of North Korean saber-rattling so close to its borders. In 2013, it admonished the garrison kingdom for its third nuclear test. Kim Jong Un reportedly also lost ground when he ordered the execution of his uncle, Jang Song Taek, who was the second most powerful man in the nation and a point man for natural resource sales to China.

And Beijing has long wanted Pyongyang to adopt its brand of socialist-market development, with little apparent progress.

In turn, North Korea has sought a handful of other potential suitors. Last summer, Pyongyang oddly appealed to historical arch-enemy Japan, opening an investigation into its kidnappings of Japanese nationals in the 1970s and 1980s in exchange for a relaxation of sanctions.

Such diplomacy didn’t get very far, with Tokyo complaining that North Korean promises fell flat.

Recently, a more appropriate partner has emerged: Putin’s Russia.

On Jan. 31, Russia’s armed forces chief of staff, Valery Gerasimov, made a surprise announcement that his government is entering “preliminary negotiations” with North Korea, Cuba and two other countries to conduct joint naval, air, and ground exercises.

If that’s not enough, Russian Foreign Minister Sergei Lavrov told reporters on Jan. 21 that Kim Jong Un could attend a ceremony marking the 70th anniversary of the end of World War II, with a positive “first signal” from Pyongyang. If true, this would be the reclusive Kim's first official state visit.

Pyongyang, though, hasn’t confirmed the marshal’s attendance through state mouthpieces KCNA or the Rodong newspaper. It’s also possible Pyongyang will send another high-ranking official in his place.

Should this relationship come to fruition, both sides have something to gain.

Russia seeks to resist international isolation and demonstrate its solidarity against the West, in response to the outcry over the Ukraine war and last year’s Crimea annexation, say analysts.

North Korea, in its never-ending state of military emergency, needs patrons who can lend a helping hand. As Chinese friendship wanes, this is becoming ever-more crucial.

In January, North Korea urged the US and South Korea to halt its two annual joint drills this spring, called Foal Eagle and Key Resolve. It will likely respond with symbolic shows of military force, which would include exercises.

But there’s potentially more here than just geopolitics. “Russia is a very old flame,” said Andrew Salmon, military historian and author of "Modern Korea: All That Matters."

“After all, Stalin signed off on [Kim Jong Un’s] grandfather’s invasion of South Korea” — referring to the Korean War of 1950 to 1953 — “and given its own current pariah status, looks happy to further snub the international community with this step.”

“I am sure that there has been some interchange between the militaries in the decades since,” he said.