In his call with Chinese President Xi Jinping, US President Joe Biden on Friday described to him the implications and consequences if China provides material support to Russia as it conducts brutal attacks against Ukrainian cities and civilians, the White House said.

The about two-hour-long conversation between the two leaders over a secure video call focused on Russia’s invasion of Ukraine, it said.

“President Biden detailed our efforts to prevent and then respond to the invasion, including by imposing costs on Russia. He described the implications and consequences if China provides material support to Russia as it conducts brutal attacks against Ukrainian cities and civilians,” the White House said in a readout of the call.

White House Press Secretary Jen Psaki said the vast majority of the nearly two hours was spent with the president outlining the views of the United States, its allies and partners on this crisis, including a detailed overview of efforts to prevent and then respond to the invasion, “how we got here, steps we've taken, where we've gone and why”.

A senior administration official told reporters that the conversation was direct.

“It was substantive and it was detailed. The two leaders spent the preponderance of their time discussing Russia's unprovoked and unjustified invasion of Ukraine, as well as the implications of the crisis for U.S.-China relations and the international order,” the official said.

“Biden shared with Xi a detailed review of how things have developed to this point, his assessment of the situation today, and President Biden underscored his support for a diplomatic resolution to the crisis,” the official said, adding that Biden described the US’ assessment of Putin's actions and his miscalculations.

“He also described the unity of the United States and its allies and partners, the unprecedented coordination with our European, NATO, and Indo-Pacific partners, and the overwhelming global unity and condemnation of Russia's invasion of Ukraine, as well as the support for Ukraine,” said the official.

“Biden made clear the implication and consequences of China providing material support -- if China were to provide material support -- to Russia as it prosecutes its brutal war in Ukraine, not just for China's relationship with the United States but for the wider world,” the official said.

During the call, Biden stressed concerns that Russia is spreading disinformation about biological weapons in Ukraine as a pretext for a false-flag operation and underscored concerns about echoing such disinformation.

“President Xi raised Taiwan. President Biden reiterated that the United States remains committed to our one-China policy and is guided by the Taiwan Relations Act, the Three Joint Communiqués, and the Six Assurances. And he underscored the importance of maintaining peace and stability across the Taiwan Strait,” the official said.