REUTERS

Read alsoTotal number of COVID-19 cases confirmed worldwide approaching 2.5 mln

WHO Director-General Tedros Adhanom Ghebreyesus didn't specify why he believes the outbreak that has infected some 2.5 million people and killed over 166,000 could get worse. He and others, however, have previously pointed to the likely future spread of the illness through Africa, where health systems are far less developed, as reported by ABC News.

"Trust us. The worst is yet ahead of us," Tedros told reporters from WHO headquarters in Geneva. "Let's prevent this tragedy. It's a virus that many people still don't understand."

Some Asian and European governments have gradually eased or started relaxing "lockdown" measures like quarantines, school and business closures and restrictions on public gatherings, citing a decline in the growth of COVID-19 case counts and deaths.