The two will meet again on Tuesday for official talks during Mr Xi's first visit to Moscow since the invasion.
The White House's National Security Council spokesman called on Mr Xi to urge his Russian counterpart to withdraw troops from Ukraine.
John Kirby said seeking a ceasefire would not be enough.
"We hope that President Xi will press President Putin to cease bombing Ukrainian cities, hospitals and schools, to halt the war crimes and atrocities and to withdraw his troops," he said.
"But we are concerned that instead China will reiterate calls for a ceasefire that leaves Russian forces inside Ukraine's sovereign territory and any ceasefire that does not address the removal of Russian forces from Ukraine would effectively ratify Russia's illegal conquests."
In another development, Japan's Prime Minister, Fumio Kishida, is making a surprise visit to Ukraine for talks with President Volodymyr Zelensky. He is expected to voice solidarity and support for Ukraine following Russia's invasion.
Japan and China see each other as regional rivals. Since Russia's war in Ukraine began, Tokyo has provided Kyiv with a mixture of humanitarian, financial and non-lethal military aid.