"You are not invincible. This virus could put you in hospital for weeks or even kill you," the World Health Organization (WHO) director general said in Geneva.

The pandemic, which has resulted in more than 210,000 confirmed infections and 9,000 reported deaths requires not only cooperation among countries but also among generations, Tedros stressed.

"I'm grateful that so many young people are spreading the word and not the virus," the WHO chief said, commending young people who are protecting elders by protecting themselves.

Tedros also sent out a message to the millions who are forced to stay indoors as their authorities have imposed various forms of lockdowns.

Confined people should take extra care to eat healthy food, to avoid tobacco and alcohol, and to take good care of their bodies and minds.

"If you can't leave the house, find an exercise video online, dance to music, do some yoga, or walk up and down the stairs," the Ethiopian UN health chief said.

Keeping in contact with family and friends, and reaching out to neighbours is another way to protect one's well-being, according to Tedros.

Earlier on Friday, UN agencies warned that the pandemic creates risks for billions of people who cannot wash their hands properly, and for hundreds of millions of children who have to cope without school lunches as education facilities are shuttered.

Three billion people around the world have no adequate access to water or soap to wash their hands, the United Nations said in Geneva, citing WHO and UN Children's Fund (UNICEF) data.

Australian Associated Press