The leaders of North Korea and China marked the 75th anniversary of their diplomatic relations on Sunday by exchanging messages that expressed hopes for stronger ties.

The message exchange came as North Korea and Russia have been sharply expanding their cooperation while China keeps its distance.

Experts say that the level of exchanges and commemorative programs between North Korea and China in the coming months will provide a clue to the exact status of their ties.

In a message sent to Chinese president Xi Jinping, North Korean leader Kim Jong Un said his government will “steadily strive to consolidate and develop the friendly and cooperative relations” between the two countries, according to North Korea’s official Korean Central News Agency.

Mr Xi, in his message to Kim, said that China is ready to jointly promote “the stable and further advance of the socialist cause in the two countries,” KCNA said.Since North Korea and China established diplomatic ties on October 6, 1949, their relationship has often been described as being “as close as lips and teeth.”

China, North Korea’s biggest trading partner and main aid provider, has been suspected of avoiding fully implementing UN sanctions on North Korea and sending clandestine aid shipments to help its impoverished neighbour stay afloat and continue to serve as a bulwark against US influence on the Korean Peninsula.

However many observers say China is reluctant to form a three-way, anti-West alliance with North Korea and Russia as it prefers a stable regional security environment to tackle numerous economic challenges and maintain relationships with Europe and its Asian neighbours.

North Korea and Russia have moved significantly closer to each other amid widespread outside suspicions that North Korea has supplied conventional weapons to Russia for its war in Ukraine in return for military and economic assistance.

During a meeting in Pyongyang in June, Mr Kim and Russian president Vladimir Putin signed a pact stipulating mutual military assistance if either country is attacked, in what was considered the two countries’ biggest defence deal since the end of the Cold War.

North Korea is locked in confrontations with the US, South Korea and their partners over its advancing nuclear program. Mr Kim has said he was forced to expand both nuclear and conventional capabilities to cope with US-led security threats.

On Sunday, KCNA reported that Mr Kim oversaw a live artillery firing drill by cadets of a military academy.

After watching the drill, Mr Kim said training programs at the military academy must focus on “the guerrilla war tactics to wipe out the enemies through rapid mobile and surprise operations,” according to KCNA.