Joe Biden has said “everybody” should be concerned about monkeypox outbreaks.
It comes as Israel and Switzerland became the latest countries to report cases of the disease, bringing the total - which includes the UK - to 14.
US president Biden, in his first public comments on the monkeypox outbreak on Sunday, said it is something "everybody should be concerned about" and that “we’re working on it hard to figure out what we do”.
“It is a concern in that if it were to spread it would be consequential,” Biden said.
The UK Health Security Agency (UKHSA) - which has said the overall risk remains low - has so far confirmed 20 cases in the UK, with updated numbers set to be released on Monday.
Dr Susan Hopkins, a chief medical adviser at the agency, said more cases are being detected daily and that there is now community transmission.
Speaking to the BBC’s Sunday Morning programme, she said: “Absolutely, we are finding cases that have no identified contact with an individual from west Africa, which is what we’ve seen previously in this country.
“The community transmission is largely centred in urban areas and we are predominantly seeing it in individuals who self-identify as gay or bisexual, or other men who have sex with men.”
While there is no direct vaccine for monkeypox, Dr Hopkins added doctors are using a form of smallpox vaccine - which has effectiveness against monkeypox - for those who have come into contact with cases.
What is monkeypox, how does it spread and what are its symptoms?
Monkeypox cases are usually found in west Africa, and the virus does not often spread elsewhere.
That is why the outbreaks reported in Europe, Canada, Australia and the US have caused alarm among public health experts - though leading UK scientists have said it won’t be the next pandemic.
The disease, which was first discovered in monkeys, is usually mild but can cause severe illness in some cases.
It can be transmitted from person to person through close physical contact, including sexual intercourse.
It can also spread through touching clothing, bedding or towels used by someone with the monkeypox rash, and through the coughs and sneezes of somebody with the infection.
Watch: Monkeypox poses threat to sexual health services - GP
However, the UKHSA says the virus does not usually spread easily between people and the risk to the UK population overall remains low.
Symptoms include fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion.
A rash can develop, often beginning on the face, which then spreads to other parts of the body including the genitals.
The rash can look like chickenpox or syphilis, and scabs can form which then fall off.
The incubation period of monkeypox is usually from six to 13 days but can range from five to 21 days.