China has vehemently denied a report that it asked Moscow to delay its invasion of Ukraine until after the Winter Olympics, denouncing it as “fake news”.

“This kind of rhetoric is to divert attention and shift blame, which is utterly despicable,” Wang Wenbin, a Chinese foreign ministry spokesperson, said on Thursday when asked by journalists about the New York Times report published on Wednesday.

Russia launched its attack on Ukraine on 24 February, four days after the end of the Games. On 21 February, Vladimir Putin recognised the independence of separatist-held territories of eastern Ukraine and ordered in troops.

Wang again blamed Nato’s eastward expansion and the US administration’s attitude towards Ukraine’s Nato membership for the deterioration of relations with Russia. He said the cause of the current crisis was “a fact known by heart to all”. “Only those who start the problem can end it,” he added.

According to the New York Times, which quoted Biden administration officials and a European official who cited a western intelligence report, senior Chinese officials told their Russian counterparts in early February not to invade Ukraine before the conclusion of the Winter Olympics in Beijing.

The report said the intelligence on the exchange between the Chinese and Russian officials was classified, and it was unclear whether the exchange took place in a face-to-face conversation between Xi Jinping and Putin in early February, or through other channels.

It said different intelligence services had varying interpretations, and it was not clear how widely the information was shared.

The impact of Russia’s invasion appears to have caught China’s diplomats off guard. Citing a separate source, the Hong Kong-based South China Morning Post said it was “apparent from Beijing’s lack of warning to its approximately 6,000 citizens stranded in Ukraine in recent days – amid news that a Chinese national was wounded by gunfire – that it did not expect a major war.”

In the past week, as the war raged on, China signalled it was willing to play the role of a mediator. Beijing said it “laments” the outbreak of the conflict. It asked the Ukrainian side to provide assistance to Chinese nationals who were finding it difficult to leave.

While western sanctions have imposed sanctions on Russia, China said on Wednesday that it would not follow suit. “We will not participate in such sanctions. We will continue to maintain normal economic and trade exchanges with relevant parties,” said Guo Shuqing, the chair of the China Banking and Insurance Regulatory Commission.

The New York Times said the intelligence report indicated senior Chinese officials had some level of knowledge about Russia’s plans or intentions to invade Ukraine before Moscow launched the operation last week, which has so far killed thousands of civilians and forced at least a million Ukrainians to flee home, according to the UN.

Separately, a source familiar with the matter confirmed to Reuters that China had made the request but declined to provide details. The source declined to be identified owing to the sensitivity of the matter, the Reuters report said.

A spokesperson for the Chinese embassy in Washington, Liu Pengyu, said on Wednesday that the claims were “speculations without any basis and are intended to blame-shift and smear China”.

The US state department, the CIA and the White House national security council have not commented on the allegations.

On Wednesday the United Nations general assembly overwhelmingly voted to reprimand Russia for invading Ukraine and demanded that Moscow stop fighting and withdraw its military forces. China and India abstained in the vote.