The World Health Organization on Monday reiterated that it has kept no secrets about the spread of the coronavirus, after United States President Donald Trump has repeatedly accused the organisation of downplaying the extent of the Covid-19 outbreak in China.

Director General Tedros Adhanom Ghebreyesus said in a virtual briefing: “We have been warning from day one that this is a devil that everyone should fight. There is no secret in WHO because keeping things confidential or secret is dangerous. It’s a health issue.”

Tedros said the presence of embedded US government officials working at the organisation’s headquarters in Geneva was testament to the WHO’s transparency, and the fact that it had not concealed any facts from Washington.

The health body claimed there were 15 staff from the US Centers for Disease Control and Prevention detailed specifically to work with the organisation on its Covid-19 response. “WHO is open. We don’t hide anything,” Tedros said.

“Not only for Centers for Disease Control and Prevention, or others – we want all countries to get the same message immediately because that helps countries to prepare well and to prepare quickly,” he added. “At WHO, we are an open book.”

In its staunch criticism for the health body, the US has also questioned why it did not pursue a lead from Taiwan flagged on December 31 about reports of atypical pneumonia in Wuhan. Last week, the United States said it was “deeply disturbed” that Taiwan’s information was withheld from the global health community, “as reflected in the WHO’s January 14 statement that there was no indication of human-to-human transmission”.

However, Tedros insisted that the WHO was already aware of reports emanating from Wuhan, and that Taiwan had not reported any human-to-human transmission. “One thing that has to be clear is the first email was not from Taiwan,” he said. “Many other countries were already asking for clarification. The first report came from Wuhan.”

The health body called the coronavirus “public enemy number one” and said the “the worst is yet ahead of us” in the pandemic, as countries around the world eased restrictions on the movement of people imposed to flatten the transmission curve.

“We want to re-emphasise that easing restrictions is not the end of the epidemic in any country,” Tedros said. “So-called lockdowns can help to take the heat out of a country’s epidemic, but they cannot end it alone.”

He said countries must ensure they are able to detect, test, isolate and take care of every coronavirus patient, and trace every contact. “Trust us. The worst is yet ahead of us,” he said. “Let’s prevent this tragedy. It’s a virus that many people still don’t understand.”

The WHO chief said only a tiny proportion of the global population – maybe as few as 2% or 3% – appear to have antibodies in the blood showing they have been infected with Covid-19. However, while antibody tests are important for knowing who has been infected, tests that find the virus are a core tool for active case finding, diagnosis, isolation and treatment, he added.

The health body also said that it intends to ship more than 180 million surgical masks, 54 million N95 masks, along with over three million protective goggles to countries that need them the most.

The worldwide toll from the coronavirus pandemic has crossed 1.7 lakh and more than 24.75 lakh declared cases have been found in 185 countries and territories, according to the Johns Hopkins University tracker.