I seriously doubt that the North Korean troop dispatch to Russia was not cordinated with China in the first place. This phone calls seems more about optics of appearing to do something instead of actually expecting something to be done:
U.S. President Joe Biden called Saturday for China to use its clout to prevent an escalation of Russia’s war in Ukraine through the dispatch of more North Korean troops, while raising concerns over the possibility of Pyongyang engaging in provocations, a senior U.S. official said Saturday.
National Security Adviser Jake Sullivan elaborated on the discussions that Biden and Chinese President Xi Jinping had during their talks on the margins of the Asia-Pacific Economic Cooperation summit in Lima, amid mounting concerns about broad security implications of a military alignment between Moscow and Pyongyang.
“(Biden) also pointed out (to Xi) that the PRC does have influence and capacity and should use it to try to prevent a further escalation or further expansion of the conflict through the introduction of even more DPRK forces,” Sullivan told reporters in a press briefing.
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