The new cases identified in the UK, brings the total number of confirmed cases of the disease to seven, health bosses have said.
Three of the cases have been detected in London, and one in the North East of England, the UK Health Security Agency (UKHSA) announced on Monday.
The health agency is working to find links between the latest four cases, which all appear to have been infected in the capital.
Common contacts have been established between two of the four individuals who have caught the virus.
Those needing care are being treated in specialist infectious disease units at the Royal Free Hospital, Royal Victoria Infirmary in Newcastle upon Tyne and Guy’s and St Thomas’.
These cases do not, however, seem to be connected to the previous confirmed cases of monkeypox in the UK which were announced on May 14, nor the first UK case announced on May 7, which has led to concerns that there has been transmission of the virus in the community.
Health Experts ‘rapidly investigating’ spread of monkeypox in UK
Dr Susan Hopkins, chief medical adviser at the UKHSA said: “This is rare and unusual.
“UKHSA is rapidly investigating the source of these infections because the evidence suggests that there may be transmission of the monkeypox virus in the community, spread by close contact.
“We are particularly urging men who are gay and bisexual to be aware of any unusual rashes or lesions and to contact a sexual health service without delay.
“We are contacting any potential close contacts of the cases to provide health information and advice.”
What are the symptoms of monkeypox
The rash, which can develop as part of the virus, changes and goes through different stages before finally forming a scab, which later falls off.
The health agency also said that initial symptoms of monkeypox include fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion.