Director-General of the World Health Organization (WHO) Tedros Adhanom Ghebreyesus has issued a warning to world leaders that the Covid-19 pandemic "is nowhere near over".
The WHO chief cautioned against the assumption that the newly dominant Omicron variant is significantly milder and has eliminated the threat posed by the virus, the BBC reported.
The intervention comes as some European nations saw record new case numbers.
Speaking during a news conference at the WHO headquarters in Geneva, Tedros told reporters that the Omicron variant had led to 18 million new infections across the world over the past week.
While the variant may prove to be less severe on average, "the narrative that it is a mild disease is misleading", he said.
"Make no mistake, Omicron is causing hospitalisations and deaths, and even the less severe cases are inundating health facilities."
He warned global leaders that "with the incredible growth of Omicron globally, new variants are likely to emerge, which is why tracking and assessment remain critical".
"I remain particularly concerned about many countries that have low vaccination rates, as people are many times more at risk of severe illness and death if they are unvaccinated," he added.
The WHO's emergencies director, Mike Ryan, also warned that Omicron's increased transmissibility is likely to drive a rise in hospitalisations and deaths, especially in nations where fewer people are vaccinated.
"An exponential rise in cases, regardless of the severity of the individual variants, leads to inevitable increase in hospitalisations and deaths," he said.