“Knowing the source of the virus is very, very important,” the WHO director-general Tedros Adhanom Ghebreyesus told a virtual press conference on Monday.

“We can fight the virus better when we know everything about the virus, including how it started,” he said, The Guardian reported.

“We will be sending a team next week to China to prepare for that and we hope that that will lead to understanding how the virus started.”

Tedros did not specify the make-up of the team, or what specifically its mission was. Scientists believe the virus jumped from animals to humans, possibly at a market in Wuhan selling exotic animals for meat.

The WHO chief also warned that the pandemic was “speeding up” and was far from over, saying he feared “the worst is still to come” unless international unity replaces fractious division.

As cases continued to rise in the US, the states of Arizona, Texas, Florida and California all imposed new restrictions on residents, backtracking on measures to reopen. Oregon and Kansas will required to wear masks in public, it was announced on Monday, while New York state governor Andrew Cuomo called on President Donald Trump to issue a nationwide order requiring face coverings to be worn in public.

The US alone accounts for more than a quarter of the world’s coronavirus cases, with close to 2.6 million confirmed infections, and 126,131 deaths. The global death toll stands at 504,927, while cases neared 10.3m on Tuesday.

The disease’s toll is worsening in other countries, too. In the UK, which has the third-highest number of deaths globally, the government imposed the first local lockdown measures – in the city of Leicester – which has a much higher COVID-19 infection rate than anywhere else in Britain. Non-essential shops will close from Tuesday and, as will schools from Thursday. It comes as the rest of England is looking forward to many restrictions lifting this weekend.

Iran, meanwhile, reported its highest one-day death toll of the pandemic so far, with 162 fatalities according to government sources. Known cases in Iran, which has the tenth-highest confirmed infections worldwide, number 225,205, with deaths at 10,670. It was one of the first countries to report significant cases in the pandemic, outside of China.

New Zealand, however, has cause for celebration, after it confirmed no new cases of COVID-19, after two weeks with a number of cases in returning travelers. In a press conference on Tuesday, Prime Minister Jacinda Ardern dismissed calls to open the country’s borders.

At a news conference in Wellington, Ardern said the pandemic “is escalating not slowing, and not even peaking in some countries yet,” but that, “all of the while, we get to enjoy weekend sport, go to restaurants and bars, our workplaces are open, and we can gather in whatever numbers we like.”

“These are hard-won gains, and we have as a government no intention of squandering them,” Ardern said.

New Zealand has 22 active cases of COVID-19, all diagnosed during routine testing of returning travelers. There is no known community transmission in the country.

Other recent developments in the pandemic include:

In New York, Broadway theatres will remain closed until at least January 2021, the industry group the Broadway League has said, extending their coronavirus-related shutdown for another four months.

The 2021 Asia-Pacific Economic Cooperation (APEC) Summit will be hosted virtually due to COVID-19. The major gathering of Asia-Pacific world leaders – including the USA, China, Japan, Russia, and Australia – was to be staged in Auckland, New Zealand for the first time in 22 years.

Researchers in China have discovered a new type of swine flu that is capable of triggering a pandemic, according to a study in the US science journal PNAS.

In the state of Victoria, in Australia, 64 new coronavirus cases were confirmed, as the state struggled to contain the worst outbreak in the country.