North Korean leader Kim Jong-un, left, and Chinese President Xi Jinping walk together during a visit to Dalian, China, May 8, 2018. Yonhap

The Sino-North Korean alliance, historically a cornerstone of Pyongyang's foreign policy, appears to be experiencing unprecedented strain. As North Korea's strategic embrace of Russia deepens, characterized by military cooperation and a growing ideological affinity, Beijing finds itself navigating a precarious balancing act, foreign relations experts said.

They pointed out that bilateral relations have hit a low point, making any significant improvements unlikely in the foreseeable future.

"The outlook is not easy to predict due to many variables," said Professor Park Won-gon of Ewha Womans University. "The primary variable is the Russia-Ukraine war, and the second is how quickly and at what level [U.S. President Donald] Trump, as he has announced, establishes a communication channel with Kim Jong-un. These two are the key factors."

Park emphasized that China's stance of non-intervention in the Ukrainian conflict clashes with North Korea's active military support for Russia. This divergence in strategic approach has inevitably created a rift between the two allies.

In October, North Korea deployed approximately 10,000 troops to Russia to bolster its military efforts in Ukraine. This move provided North Korea with financial benefits, addressing its need for foreign currency.

However, this move also raises concerns about North Korea's escalating military capabilities, potentially destabilizing the regional security landscape, experts said.

"North Korea has been talking about a new Cold War, as Kim Jong-un mentioned recently," Park added. "At a plenary meeting, North Korea continued to emphasize its bloc policy, which makes China uncomfortable. China has been opposing the formation of regional blocs and is trying to maintain a certain distance from North Korea."

While acknowledging China's strategic interest in maintaining North Korea as a buffer zone, Yang Moo-jin, president of the University of North Korean Studies, emphasized the inherent dilemma Beijing faces in balancing its ties with both the North and Russia within the context of its broader geopolitical competition with the United States.

"China cannot fully bring North Korea to its side nor can it push North Korea away. As North Korea-Russia relations become closer, China feels more isolated. It's quite an ironic situation. If North Korea receives advanced military technology support from Russia in return for military dispatches, this could make China very uncomfortable," Yang said.

"With North Korea potentially enhancing its asymmetrical capabilities and conventional weapons with Russian support, China could find it harder to control North Korea, which is not a scenario Beijing desires. The provision of conventional weapons support from Russia to North Korea would be a significant concern for the U.S., South Korea, Japan and China," he said.

Russian President Vladimir Putin, left, shakes hands with North Korean leader Kim Jong-un during a meeting in Pyongyang, June 19. Yonhap-AFP

Compounded by these challenges, experts do not foresee an immediate improvement in relations.

"The situation will likely remain as it is. The relationship with China is already at its lowest point, so it is unlikely to get worse," Park said.

Last year marked the 75th anniversary of diplomatic relations between North Korea and both China and Russia. In socialist countries, significant anniversaries, such as the fifth or 10th year, are held in high regard. North Korea declared 2024 as the "Year of China-North Korea Friendship." However, there appeared to be markedly fewer high-level exchanges throughout the year than before.

The lack of meaningful events to commemorate this milestone between North Korea and China was telling. The most critical aspect was the absence of a meeting between Chinese President Xi Jinping and Kim, while, in contrast, Russia's President Vladimir Putin visited Pyongyang in June, even forging a new alliance treaty, according to the experts.

On June 19, Putin and Kim met in Pyongyang, further solidifying the growing alliance between the two nations. The summit marked the first time in over two decades that a Russian president visited North Korea, signaling a deepening of military, economic, and diplomatic relations.

North Korea has openly displayed its closeness with Russia. For example, the full text of a New Year's greeting from Russian President Vladimir Putin was featured prominently on the front page of the Rodong Sinmun, North Korea's state-run newspaper.

Meanwhile, a New Year's message from the Chinese president was briefly mentioned alongside other world leaders' greetings. Additionally, while North Korean leader Kim Jong Un's reply to Putin was publicly disclosed, there has been no information on whether he sent a response to Xi.

This disparity in engagement, coupled with reports of increased pressure on North Korean workers in China, paints a grim picture of a relationship teetering on the brink, according to experts. While a complete rupture is unlikely, the Sino-North Korean alliance, once a pillar of regional stability, now appears to be navigating uncharted and potentially turbulent waters, they added.