Chinese foreign ministry spokeswoman Hua Chunying said that since the outbreak began last month, “the Japanese government and its people from all walks of life have expressed sympathy, understanding and support to us”, adding that she was “deeply touched”.

She cited donations of masks, goggles and protective gear – which are in short supply in China – and lighting up the Tokyo Skytree broadcasting and observation tower in red and blue to pray for the country.

Hua continued: “In response to the extreme and discriminatory words uttered by some countries, officials from the Japanese Ministry of Health, Labour and Welfare countered … that what is at fault here is the virus, definitely not people.

“I believe many Chinese netizens have also noticed these heart-warming details,” she said. “We thank people from any country who have shown sympathy, understanding and support during this difficult time. We will keep this in our hearts.”

Hua did not elaborate on the “extreme and discriminatory words”, but on Monday Beijing criticised Washington for closing its borders to visitors who had been to mainland China.

Hua said Beijing had “noted the US has repeatedly expressed readiness to offer China assistance, and we hope such assistance will materialise at an early date”.

On Monday, Hua said the US was “the first” country to withdraw consulate staff from Wuhan, the epicentre of the outbreak, and impose an entry ban on Chinese travellers.

The US Centres for Disease Control and Prevention defended its “aggressive actions”, calling them “science based”. Nancy Messonnier, director of the CDC’s National Centre for Immunisation and Respiratory Diseases, said they were aimed at “slowing the entry of the virus into the United States”.

The measures were taken as the pneumonia-like illness continues to spread rapidly. The US had reported 11 confirmed cases of the coronavirus as of Monday. Dozens of other countries have restricted travel to China in an effort to curb the spread of the virus, including Singapore, Australia and Indonesia – all of which have barred entry to non-citizens who have travelled to China within the past 14 days.

But despite the apparent tension between China and the US, observers were optimistic that the coronavirus outbreak could be an opportunity to put rivalries aside and cooperate.

“This crisis, ironically, may put the brakes on a new Cold War between the two countries, albeit temporarily,” said Zhang Baohui, director of the Centre for Asian Pacific Studies at Lingnan University in Hong Kong.

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He said the situation highlighted the importance of global cooperation, and expected the “great power rivalries” that had shaped international politics recently to be put on hold.

“The US has shown it is willing to help China and its people,” he said, noting that President Donald Trump and Vice-President Mike Pence, a China hawk, had both expressed commitment to working with the country to battle the virus.

“This crisis may actually ease the profound security mistrust between the two countries,” Zhang said.

International organisations and other countries including Japan and South Korea have been shipping humanitarian aid to China amid an acute shortage of medical equipment, masks and other protective gear. The European Union has also pledged to provide assistance and supplies to China.

John Sitilides, a geopolitical strategist at Trilogy Advisors in Washington, said Beijing’s sceptical response to the US offer of help was most likely due to a fear that foreign health experts could “discover and reveal” what the Chinese authorities had initially “sought to conceal”.

That included details such as the pace of human-to-human transmission of the virus and accurate numbers of cases and deaths, he said.

The top priority for the Chinese authorities was to control the outbreak “as independently as possible” so as to project an image of the country as a “self-reliant global superpower”, he said.

Sitilides added that the US move to restrict visitors from China had nothing to do with the countries’ rivalry. In most democratic societies, “the safety and health of national populations based on open and immediate communication of life-or-death information are the paramount considerations” above any diplomatic or trade concerns, he said.