Europe is the center of a global outbreak of the virus with 90% of confirmed monkeypox cases reported there, according to the WHO. New infections have tripled since June 15 with 4,500 confirmed cases across 31 European nations.

Henri Kluge, the head of WHO Europe, called on governments to ramp efforts to prevent monkeypox from establishing itself on the continent, warning that time is of the essence.

“Urgent and coordinated action is imperative if we are to turn a corner in the race to reverse the ongoing spread of this disease,” Kluge said.

The World Health Organization on Saturday declined to declare monkeypox a public health emergency of international concern, its highest alert level. However, WHO chief Tedros Adhanom Ghebreyesus said monkeypox is an evolving health threat. Tedros called on governments to step up surveillance, contact tracing and to make sure people at high risk have access to vaccines and antivirals.