Washington DC - President Joe Biden warned Thursday that China would have a "price to pay" if it undermines Western sanctions on with Russia over its invasion of Ukraine.

Biden's high-stakes press conference followed a NATO declaration that pledged $43 billion in military funding for Ukraine, while also criticizing China.

"We have to make sure that [President Xi Jinping] understands there's a price to pay for undercutting both the Pacific basin, as well as Europe, and it relates to Russia and dealing with Ukraine," Biden said Thursday.

While insisting that he maintained good relations with his Chinese counterpart, the president said the US and NATO would react strongly if Beijing continued to assist Russia in obtaining weapons for its war.

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"They're not supplying weapons themselves, they are supplying mechanisms for [Russia] to be able to get weapons," Biden said. "Xi believes that China is a large enough market that they can entice any country... to invest there in return for commitments."

"What China has to understand is that if they are supplying Russia with information and capacity, along with working with North Korea and others... They are not going to benefit economically as a consequence."

Chinese Foreign Ministry spokesperson Lin Jian responded by blasting the tough talk as "scaremongering" and "a product of the Cold War mentality."

On Ukraine, Jian said that NATO's accusation is "ill-motivated and makes no sense," and blasted the alliance of spreading disinformation and "smearing" China.

"To this day, there’s still no end in sight for the Ukraine crisis," Jian said.

"Who exactly is fueling the flames? Who exactly is 'enabling' the conflict? The international community is not blind."

The diplomatic spat came as China conducted military drills in Europe, in Belarus and then along the southern coast of Russia.