Two more cases of monkeypox have been detected in the UK, health authorities said.
One of the new cases was found in London and the other was found elsewhere in southeast England.
Nine cases have now been confirmed since 6 May, all of them in England, the UK Health Security Agency (UKHSA) said.
The latest six are expected to have spread within the country as the infected people have no travel links to countries where monkeypox is endemic.
Health officials are investigating links between the infected people. The most recent two are not known to have any connections with earlier cases.
On Monday, the UKHSA reported four new cases – three in London and one in northeast England. All were gay or bisexual men and appeared to have been infected in London.
As a typically mild, self-limiting viral disease which does not easily spread between people, the risk posed to the general UK population is low, UKHSA said.
But the authority is advising the public, particularly gar or bisexual men, to be alert to any unusual rashes or lesions on any part of their body, particularly their genitals.
Initial symptoms of monkeypox include fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion.
Monkeypox is a disease usually linked to west Africa. The first case of the recent series was detected on 6 May in a person who had recently returned from Nigeria but, since subsequent cases were found without travel links, health officials think the virus is now likely spreading within Britain.
Dr Susan Hopkins, chief medical adviser at UKHSA, said: “These latest cases, together with reports of cases in countries across Europe, confirms our initial concerns that there could be spread of monkeypox within our communities.
“UKHSA has quickly identified cases so far and we continue to rapidly investigate the source of these infections and raise awareness among healthcare professionals.”
The UK reported its first cases of monkeypox in 2018, when three people contracted the virus after a man travelled back from Nigeria.
The virus first emerged in a human in the Democratic Republic of the Congo in 1970 and has since been detected in 11 central and west African countries.
There is no cure for monkeypox. Symptoms typically start to appear between five and 21 days after exposure, while most people recover from the illness within a matter of weeks.