Regional authorities in Madrid reported 14 confirmed cases of monkeypox this morning bringing the total number of cases to 21 in Spain.
There are another 20 suspected cases, 19 in the central region of Madrid and one in the Canary Islands, health authorities said.
Monkeypox is a usually mild viral infection. Symptoms include fever, headaches and skin rashes.
Several cases have been detected in Britain - where authorities are offering a smallpox vaccine to healthcare workers and others who may have been exposed - and others in other parts of Europe, including in Spain's neighbour Portugal.
Spain is assessing different therapeutic options, such as antivirals and vaccines, but so far all cases have mild symptoms and therefore no specific ad hoc treatment has been necessary, Spanish Health minister Carolina Darias told reporters on Friday.