China has long been North Korea’s main ally, but its influence over the reclusive nuclear-armed state is being eroded by leader Kim Jong Un’s growing ties with Moscow.

China has long been North Korea’s main ally, but its influence over the reclusive nuclear-armed state is being eroded by leader Kim Jong Un’s growing ties with Moscow.

North Korean troops will begin fighting alongside Russian forces as soon as this weekend, Ukraine said Friday — adding new urgency to a stunning turn in the war that has alarmed the Kremlin’s foes but may also be causing a headache for its friends.

Reports confirmed by Washington this week that North Korea is sending soldiers to Russia to possible battle Ukraine have raised serious concern among the U.S. and its allies, who say their involvement marks a major escalation in the grinding conflict and could deepen security risks for North Korea’s neighbors.

It is also likely to be unwelcome news in China, which has long been North Korea’s main ally but whose influence over the reclusive nuclear-armed state is being eroded by leader Kim Jong Un’s growing relationship with President Vladimir Putin.