In a statement, WHO Director-General Tedros Adhanom Ghebreyesus said that the outbreak had grown over time, with more than 16,000 reported cases from 75 countries and territories so far.
He also added that monkeypox was a disease that was shown to spread through sexual intercourse between men.
"Although I am declaring a public health emergency of international concern, for the moment this is an outbreak that is concentrated among men who have sex with men, especially those with multiple sexual partners," Ghebreyesus said.
"It’s therefore essential that all countries work closely with communities of men who have sex with men, to design and deliver effective information and services, and to adopt measures that protect the health, human rights and dignity of affected communities," he added.
He, however, cautioned that discrimination would be as dangerous as the virus itself.
What Is Monkeypox?
Monkeypox is a viral infection caused by the monkeypox virus.
According to the WHO, monkeypox is a rare disease, which mostly occurs in tropical rainforest areas of Central and West Africa.
Though the disease is rare in humans, it can be fatal. According to the WHO, as many as one-tenth of monkeypox patients may die. The risk of fatality is also higher in younger people.
According to the UK HSA, the version detected in the UK currently is milder, and does not spread very easily.
India has so far reported 1 confirmed case.
Symptoms of monkeypox are similar to that of smallpox, although it is less dangerous than the latter. These typically include:
Swollen lymph nodes
Painful blisters on the hands, feet and face (like chickenpox)
Symptoms of monkeypox can last anywhere from two weeks to a month.