That is the highest level of warning issued by the UN agency, which currently applies only to the Covid-19 pandemic and polio.

There have been 1600 confirmed and 1500 suspected cases of monkeypox this year and 72 deaths, WHO said, in 39 countries, including those where the virus usually spreads.

Monkeypox is endemic in parts of Africa but there have been more cases both in those countries and the rest of the world in recent months. The virus causes flu-like symptoms and skin lesions, and spreads through close contact.

It is thought to be fatal in around 3-6 percent of cases, according to WHO, although no deaths have yet been reported in the outbreak outside Africa. The majority of deaths this year have been in the Democratic Republic of Congo.

WHO Director General Tedros Adhanom Ghebreyesus said that it was time to consider stepping up the response because the virus was behaving unusually, more countries were affected, and there was a need for international co-ordination.

"We don't want to wait until the situation is out of control," said WHO's emergencies director for Africa, Ibrahima Socé Fall.

The committee meeting next week will be made up of global experts, but the WHO Director General makes the ultimate decision on whether the outbreak deserves the label, known as a PHEIC.

Experts have been pushing the WHO for faster action for several weeks, following criticism of the agency's initial response to the coronavirus pandemic.

Alongside Covid-19 and polio, other disease outbreaks have been declared public health emergencies of international concern, like Ebola in 2014.

A committee can also, however, pull back from raising the alarm. When a WHO emergency committee was set up to consider whether a yellow fever outbreak in West Africa in 2016 deserved the agency's highest threat level, it ultimately decided against it.

A WHO determination that an outbreak constitutes a global health emergency can help accelerate research and funding to contain a disease.

Tedros also said that WHO was working with partners on changing the name of monkeypox and its variants, as well as on a mechanism to help share available vaccines more equitably.

Some countries have begun vaccinating health workers and close contacts of monkeypox patients using smallpox vaccines, a related and more serious virus that was eradicated in 1980.

WHO issued new guidelines on monkeypox vaccination earlier on Tuesday.

- Reuters