The head of the World Health Organization (WHO) warned on Monday that it was dangerous to assume the Omicron variant would herald the end of Covid-19's acutest phase, exhorting nations to stay focused to beat the pandemic.

"It’s dangerous to assume that Omicron will be the last variant and that we are in the end game," Tedros Adhanom Ghebreyesus told a WHO executive board meeting of the two-year pandemic that has killed nearly 6 million people.

"On the contrary, globally the conditions are ideal for more variants...