The World Health Organization says more than 18,000 cases of monkeypox have been reported globally from 78 countries, mainly in Europe.
WHO Director-General Tedros Adhanom Ghebreyesus told reporters on Wednesday over 70 percent of the reported cases are in the European Union and 25 percent in the Americas.
Five deaths have been reported in Africa.
The agency chief said 98 percent of the cases involved men who have sex with men.
He said monkeypox can be spread through close contact between people and on contaminated towels or bedding. He warned against defining monkeypox as a disease that is limited to a specific group.
The world health watchdog last week declared the global outbreak of the virus a "public health emergency of international concern." It says monkeypox has spread around the world rapidly through new modes of transmission about which little is known.