"The world should not be fooled by any tactical move by Russia, supported by China or any other country, to freeze the war on its own terms," Blinken told reporters.
He said the United States welcomed any diplomacy for a "just and durable peace" but raised doubts that China was safeguarding the "sovereignty and territorial integrity" of Ukraine.
"Any plan that does not prioritize this critical principle is a stalling tactic at best or is merely seeking to facilitate an unjust outcome. That is not constructive diplomacy," Blinken said.
"Calling for a ceasefire that does not include the removal of Russian forces from Ukrainian territory would effectively be supporting the ratification of Russian conquest."
Blinken, who earlier Monday announced $350 million in new US military aid to Ukraine, renewed support for the stance of Ukrainian President Volodymyr Zelenskyy who has demanded a Russian withdrawal.
"If China is committed to supporting an end to the war based on the principles of the UN Charter - as called for in point one of its plan - it can engage with President Zelenskyy and Ukraine on that basis and use its influence to compel Moscow to pull back its forces," he said.
US Skeptical of Beijing's Ukraine Peace Plan
FILE: Russian President Vladimir Putin and Chinese President Xi Jinping attend a meeting at the Kremlin in Moscow, Russia, March 20, 2023. Taken by Russian Presidential Press Service.
WASHINGTON - US Secretary of State Antony Blinken on Monday voiced skepticism over Chinese President Xi Jinping's "peace" proposals in Moscow, warning they could be a "stalling tactic" to help Russia on the ground in Ukraine.