A spat between the US and China over the novel coronavirus escalated on Tuesday as President Donald Trump angered Beijing by referring to the pathogen as the “Chinese Virus.”

The two countries have sparred over the origin of the virus for days, with a Chinese official promoting conspiracy theories claiming it was brought to China by the US army and American officials using terms seen as stigmatising a nation.

“The United States will be powerfully supporting those industries, like Airlines and others, that are particularly affected by the Chinese Virus,” Trump tweeted Monday night.

Trump’s allies had previously referred to the pandemic as the “Chinese coronavirus”.

Beijing said Tuesday it was “strongly indignant” over the phrase, which it called “a kind of stigmatisation”.

The United States should “immediately stop its unjustified accusations against China,” foreign ministry spokesman Geng Shuang told reporters.

A commentary by the official Xinhua news agency said using “racist and xenophobic names to cast blame for the outbreak on other countries can only reveal politicians’ irresponsibility and incompetence which will intensify virus fears”.

The war of words reignited diplomatic tensions between the two countries, which have tussled over trade and other disputes since Trump took office.

Trump’s comments were criticised inside the US, with warnings it could incite a backlash against the Asian-American community.

“Our Asian-American communities — people YOU serve — are already suffering. They don’t need you fueling more bigotry,” tweeted New York city mayor Bill de Blasio, whose state is one of the hardest-hit by the virus in the US.

The World Health Organization said more cases and deaths had been reported in the rest of the world than in China.

The new coronavirus virus was first detected late last year, with China’s own health officials initially saying its source was a live animal market in the central city of Wuhan, whose government had initially tried to cover up the outbreak.

However, China has sought to distance itself from the virus, saying the origin is still unknown, while seeking global goodwill by offering aid to countries facing serious outbreaks.

US Secretary of State Mike Pompeo, in a phone call he initiated with top Chinese official Yang Jiechi, voiced anger that Beijing has used official channels “to shift blame for COVID-19 to the United States,” the State Department said.

Pompeo “stressed that this is not the time to spread disinformation and outlandish rumours, but rather a time for all nations to come together to fight this common threat,” the department added.

The State Department on Friday summoned the Chinese ambassador, Cui Tiankai, to denounce Beijing’s promotion of a conspiracy theory that had gained wide attention on social media.

Foreign ministry spokesman Zhao Lijian suggested on Twitter last week that “patient zero” in the global pandemic may have come from the United States.

“It might be US army who brought the epidemic to Wuhan. Be transparent! Make public your data! US owe us an explanation,” tweeted Zhao, who is known for his provocative statements on social media.

Pompeo himself has sought to link China to the global pandemic, repeatedly referring to the “Wuhan virus” despite advice from health professionals that such geographic labels can be stigmatising.

Yang issued a “stern warning to the United States that any scheme to smear China will be doomed to fail,” Xinhua said in its summary of the call with Pompeo.

The key Chinese foreign policy leader “noted that some US politicians have frequently slandered China and its anti-epidemic efforts and stigmatised the country, which has enraged the Chinese people,” Xinhua said.

Yang called on the US side to “correct its wrongful behaviour”.

Trump is under fire over his handling of the pandemic, and his backers have sought to cast the coronavirus as a disease brought by foreigners.

Republican Senator Tom Cotton, a Trump ally, has spoken of the “Chinese coronavirus” and in a recent statement vowed, “we will hold accountable those who inflicted it on the world.”

While COVID-19 has largely come under control in China, it has killed more than 7,000 people around the world and severely disrupted daily life in Western countries.