A row has erupted after the chief of the World Health Organization (WHO) accused Taiwan's leaders of spearheading personal attacks on him.
WHO chief Tedros Adhanom Ghebreyesus said he had been subjected to racist comments and death threats for months.
But President Tsai Ing-wen said Taiwan opposed any form of discrimination, and invited Dr Tedros to visit the island.
Taiwan said it had been denied access to vital information as the coronavirus spread. The WHO rejects this. Taiwan is excluded from the WHO, the United Nations health agency, because of China's objections to its membership.
The Chinese Communist Party regards Taiwan as a breakaway province and claims the right to take it by force if necessary.
The WHO has also been criticised by US President Donald Trump, who has threatened to withdraw US funding to the agency.
What is being said?
Dr Tedros said he had been at the receiving end of racist comments for the past two to three months.
"Giving me names, black or negro," he said. "I'm proud of being black, or proud of being negro."
He then said he had received death threats, adding: "I don't give a damn."
The WHO chief said the abuse had originated from Taiwan, "and the foreign ministry didn't disassociate" itself from it.
His words, uniquely personal and passionate, came as he called on countries around the world not to politicize the coronavirus pandemic. In particular, Tedros called on China and the US to work together, with a thinly-veiled message to President Donald Trump, who recently threatened to stop funding the WHO. "If you don't want any more body bags, then you refrain from politicizing it," Tedros said.
Ghebreyesus brushed off these personal attacks on Wednesday in a press conference, but said a line was crossed when people insulted Africa.
He would have been alluding to rumours being circulated about vaccines being tested in Africa.
"Then I don't tolerate [it], then I say people are crossing a line…we cannot tolerate that," he said.
"When it's personal, when it's death threats, I didn't care, I didn't respond… I am a very proud black person.
"I assure you, we [as WHO] will do everything we can to serve humanity. We will do everything to help us have no regrets at all."
Tedros also referenced remarks made by scientists on French TV that Tedros had condemned on Monday as artifacts of a “colonial mentality.” The scientists were discussing the potential of moving a vaccine trial in Europe and Australia to Africa, according to the BBC. Tedros said Wednesday that the remarks insulted “the whole black community.”
But Ms Tsai said Taiwan was opposed to discrimination.
"For years, we have been excluded from international organisations, and we know better than anyone else what it feels like to be discriminated against and isolated," Reuters news agency quoted her as saying.
"If Director-General Tedros could withstand pressure from China and come to Taiwan to see Taiwan's efforts to fight Covid-19 for himself, he would be able to see that the Taiwanese people are the true victims of unfair treatment."
Taiwan foreign ministry spokeswoman Joanne Ou said the comments were "irresponsible" and the accusations "imaginary". The ministry said it was seeking an apology for "slander", AFP news agency reported.
Correspondents say Taiwan has been proud of its measures to contain the virus, with just 380 cases and five deaths so far.
Last month, the WHO said it was monitoring the progress of the virus in Taiwan and learning lessons from its efforts.