Washington DC - The US government has criticized a meeting between Chinese President Xi Jinping and Russian President Vladimir Putin.

"This is not the time for any kind of business as usual with Mr. Putin given what he's done inside Ukraine," said John Kirby, the coordinator for strategic communications at the National Security Council.

"The whole world should be lined up against what Mr. Putin is doing," he added.

Kirby warned that "China has a choice to make." While he acknowledged that China had not condemned Russia's invasion, he said that China had not given its support to Russia either.

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The Chinese "haven't weighed in to violate the sanctions and they haven't also weighed in to materially support Mr. Putin," Kirby said.

He also said that the meeting between the two presidents was more important for Putin, as he "is very much under strain and stress in Ukraine" amid military setbacks.

In light of this, it was fitting that Putin was trying to "cozy up to Beijing," Kirby added, even though it was still unclear whether China would offer material support.

Putin and Xi Jinping had met on Thursday on the sidelines of the summit of the Shanghai Cooperation Organization (SCO) in Samarkand, Uzbekistan. It was the first meeting between the two since the start of the Russian invasion of Ukraine.

The two leaders presented a united front, positing themselves against the US.