World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus gestures during a daily press briefing on COVID-19 virus at the WHO headquaters on March 2, 2020 in Geneva.

The coronavirus pandemic that's spread to nearly every country in the world is picking up pace, the World Health Organization said Monday, as global cases eclipsed 350,000 and deaths soared past 15,000.

"The pandemic is accelerating," WHO Director-General Tedros Adhanom Ghebreyesus said at a press briefing from the organization's Geneva headquarters. "It took 67 days from the first reported case to reach 100,000 cases, 11 days for second 100,000 cases, and just four days for the third 100,000 cases."

Tedros said he'll be asking the G20, the international group of government and central bank leaders, to ramp up production of personal protective equipment for doctors and nurses and to avoid placing export bans on the life-saving gear. WHO had already been asking suppliers of protective gear to prioritize sending the equipment to regions most affected by the virus and discouraged stockpiling of protective gear by the general public.

"We need unity among the G20 countries who have more than 80% of the global GDP," he said. "If we don't prioritize protecting health workers, many people will die because the health worker who could have saved their lives is sick."

World health officials estimate more than 26 million health-care workers may end up treating COVID-19 patients. On Friday, WHO officials warned the outbreak could overwhelm health systems around the world in just a few weeks.

"Take one look at what's happening in some health systems around the world. Look at the intensive care units completely overwhelmed. Doctors and nurses utterly exhausted," Mike Ryan, executive director of the WHO's emergencies program, said Friday. "This is not normal. This isn't just a bad flu season."

The virus is transmitted through droplets, or little bits of liquid, mostly through sneezing or coughing.

WHO has said it is are aware of several studies in a number of countries looking at the different environmental conditions that COVID-19 can persist. Scientists are specifically looking at how humidity, temperature and ultraviolet lighting affects the disease as well as how long it lives on different surfaces, including steel, they said.

Last week, health officials said parents need to prepare their kids to guard against COVID-19 after a new study showed that babies and very young children can sometimes develop severe symptoms.

The new study, which was published online in the journal Pediatrics, looked at 2,143 cases of children with confirmed or suspected COVID-19 that were reported to the Chinese Centers for Disease Control and Prevention between Jan. 16 and Feb. 8. More than 90% of the cases were asymptomatic, mild or moderate cases. However, nearly 6% of the children's cases were severe or critical, compared with 18.5% for adults.

"What we need to prepare for is the possibility that children can also experience severe disease," Dr. Maria Van Kerkhove, head of WHO's emerging diseases and zoonosis unit, said on Wednesday.