United States President Donald Trump's recent labeling of the novel coronavirus pneumonia pandemic as originating from a "Chinese virus" has triggered widespread backlash from the international community.

Officials and commentators worldwide used words like "racist" and "xenophobic" to describe the term and said it is part of Washington's attempt to shift blame to China for its delayed, inefficient response to the novel coronavirus pandemic.

Instead of terms such as "COVID-19" or "coronavirus", the US top leader used the term in both his Wednesday and Thursday news conferences at the White House as well as in some recent tweets, and he publicly rejected reporters' questions about whether the term was racist.

The World Health Organization gave the name COVID-19 to novel coronavirus pneumonia on Feb 11, when WHO's chief scientist Soumya Swaminathan said it was both for scientific purposes and also to "avoid a number of different stigmatizing or other forms of confusing names".

US Democrats have slammed Trump and other Republicans for using "Chinese" or "Wuhan" when referring to the virus in public statements and social media posts.

Former US vice-president Joe Biden on Wednesday condemned Trump's comments and urged him to "take responsibility" for his actions.

"Stop the xenophobic fearmongering. Be honest. Take responsibility. Do your job," he wrote on Twitter.

Former US secretary of state Hillary Clinton also tweeted on Wednesday that Trump was attempting to distract people from his administration's slow response to the pandemic.

"The president is turning to racist rhetoric to distract from his failures to take the coronavirus seriously early on, make tests widely available and adequately prepare the country for a period of crisis," she tweeted. "Don't fall for it. Don't let your friends and family fall for it."

The distinguished American economist Paul Krugman said in his New York Times column that the coronavirus outbreak should probably be referred to as the "Trump pandemic" as the US response to the virus has been "catastrophically slow and inadequate".

Racism and blaming other people have been the defining features Trump have used during his presidency, he added.

Josep Borrell, high representative of the European Union for foreign affairs and security policy, said on Thursday that viruses don't have a nationality and don't care about borders.

"COVID-19 is not a Chinese virus, as the Spanish flu was not Spanish," he tweeted. "We all face a massive threat that requires global cooperation and all of us working hand in hand."

Sadiq Khan, mayor of London, said on Thursday: "COVID-19 is COVID-19." He said trying to link a nation to the illness "is disgraceful."

The term used by Trump is "the sort of language which leads to incitement and hatred toward people of Chinese origin", Khan said when answering questions from members of the London Assembly about the pandemic.

"We are a city which celebrates our diversity and we think it is a strength, not a weakness. It's really important that we do not fall into the trap of some to use this virus as an excuse to denigrate, demean and humiliate people," the mayor added.

Pascal Lamy, former director-general of the World Trade Organization, said that the COVID-19 crisis is testing first and foremost the resilience of national governance, as the capacity to fight the virus lies in the quality of health systems and in collective disciplines such as social distancing.

But there is also a second order international dimension in cooperation to provide medical equipment, liquidity for economies or signals for concerted action, Lamy said.

"In this respect, I very much agree with the WHO that 'my country first' or 'blame the foreigners' political proclamations are dangerously counterproductive, including when they target China," he said.

Canadian experts and officials also stressed that using the term that Trump did does not help bring the whole world together to respond to this common threat. Only through global collaboration can the war against the virus eventually be won.

Thomas Bernes, a distinguished fellow at the Centre for International Governance Innovation, said that the terms being used by Trump are "highly regrettable and inappropriate".

"This is a global threat that requires global cooperation to defeat the virus and respond to the global economic challenge," said Bernes. "Trump's go-it-alone approach can only fail, and his language can only exacerbate problems and make global cooperation more difficult."

Toronto Councilor Jim Karygiannis said it is time for the US president to acknowledge that the term is racist and apologize for using it.

"The president continually has demonstrated that he reacts before he thinks. In this case, he is using China as a scapegoat for his country not being ready to fight the COVID-19 threat," said Karygiannis.

Leading media have also criticized the use of the term.

Amanda Walker, US correspondent of Sky News, wrote on Thursday that Trump "has recently and very purposefully ramped up his reference to 'Chinese virus'".

She noted that "there has been another recent change in Mr Trump's tone" as Trump is now "taking this public health crisis seriously" and he "accepted it could cause a recession and its grip on America could last well into the summer, which is just a couple of months from November's election.

"If millions of Americans die, it will be on his watch," Walker wrote. She said using an insulting term "is a way of deflecting blame".

The New York Times said on Thursday that Trump is "ignoring a growing chorus of criticism that it is racist and anti-Chinese".

Chen Weihua in Brussels and Rena Li in Toronto contributed to this story.