In a virtual media briefing from Geneva, WHO chief Tedros Adhanom Ghebreyesus warned the governments not to lose control over lockdowns and take strict measures to flatten the Covid-19 curve.

"We know that Covid-19 spreads fast, and we know that it is deadly, 10 times more deadly than the 2009 flu pandemic," the WHO chief stressed.

The 2009 Swine Flu pandemic was an influenza pandemic that lasted from January 2009 to August 2010, and the second of the two pandemics involving the H1N1 influenza virus, albeit a new strain. It killed 18,036 people besides infecting 6,04,446 others globally.

"This pandemic is much more than a health crisis," said the WHO chief.

As some of the European countries hardest hit by the Covid-19 pandemic are starting to see signs of slowing in infections, the WHO sounded a stern warning against lifting restrictions too soon, saying it could lead to a deadly resurgence of Covid-19.

"In the past week, we've seen a welcome slowing in some of the hardest-hit countries in Europe like Spain, Italy, Germany and France," said the WHO Director-General.

As "some countries are already planning the transition out of stay-at-home restrictions," the WHO chief warned that "lifting restrictions too quickly could lead to a deadly resurgence."

"The way down can be as dangerous as the way up if not managed properly," he said, underlining that the WHO is working with the affected countries on strategies for gradually and safely easing the restrictions.

The US has become the epicentre of the disease that originated in China late last year. The virus has so far infected over 557,000 people in the US, while more than 22,000 have died.