The new coronavirus pandemic raging around the globe will worsen if countries fail to adhere to strict healthcare precautions, the World Health Organization (WHO) warned on Monday.

"Let me be blunt, too many countries are headed in the wrong direction, the virus remains public enemy number one," WHO Director General Tedros Adhanom Ghebreyesus told a virtual briefing from the UN agency's headquarters in Geneva.

"If basics are not followed, the only way this pandemic is going to go - it is going to get worse and worse and worse."

Global infections stand at 13 million, according to a Reuters tally, with more than half a million deaths.

Tedros, whose leadership has been criticized by US President Donald Trump, said that of 230,000 new cases on Sunday, 80% were from 10 nations, and 50% from just two countries.

The United States and Brazil have been worst hit.

WHO emergencies head Mike Ryan said some places in the Americas may need "limited or geographically focused lockdowns that suppress transmission in specific areas where transmission is frankly out of control".

He urged countries not to make schools into a political football, saying schools could safely reopen once the virus had been suppressed.

Tedros said the WHO had still not received formal notification of the US pullout announced by Trump. The US president says the WHO pandered to China, where the COVID-19 disease was first detected, at the start of the crisis.

Trump, who at the weekend wore a protective face mask in public for the first time, has himself been accused by political opponents of not taking the coronavirus seriously enough, something he denies.

A two-member WHO advance team in China to investigate the origins of the coronavirus, first discovered in the city of Wuhan, is in quarantine, as per standard procedure, before beginning work with Chinese scientists, Ryan said.

The coronavirus sweeping across the world is a pandemic, the World Health Organization declared today. There are now over 118,000 cases of COVID-19, the disease caused by the virus, in 114 countries around the world.

The WHO continues to closely monitoring spread of the virus, said Tedros Adhanom, director general of the WHO, during the announcement. “We are deeply concerned both by the alarming levels of spread and severity, and by the alarming levels of inaction,” he said. “We have called every day for countries to take urgent and aggressive action.”

There are large outbreaks of the virus in Italy, South Korea, and the United States. In the US, the slow rollout of testing and limited testing capacity has crippled response to the disease.

The spread of the virus can still be controlled, Adhanom said. He pointed to both China and South Korea, where outbreaks appear to be declining. “It’s doable.”

A pandemic is the “worldwide spread of a new disease,” according to the WHO. There’s no cut-and-dry criteria for what reaches the level of pandemic and what does not, and there is no threshold of cases or deaths that triggers the definition.

The WHO classified the novel coronavirus as a global public health emergency on January 30th. Until now, they’ve been reluctant to call the outbreak a pandemic over concerns that it would incite unnecessary panic, though they’d been warning countries to prepare for a pandemic. “Using the word pandemic now does not fit the facts, but it may certainly cause fear,” Adhanom said at a press briefing at the end of February. “What we see are epidemics in different parts of the world affecting different countries in different ways.”

Countries around the world, including in the US, have already been leaning on pandemic preparedness plans to respond to outbreaks of the new coronavirus.

The last time the WHO declared a pandemic was during the H1N1 outbreak in 2009, which infected nearly a quarter of the world’s population. However, that decision was criticized for creating unnecessary panic. SARS was not considered a pandemic, despite affecting people in 26 countries, and neither was MERS.