Health officials in Florida are investigating a “presumptive” monkeypox case, the third reported in the United States.
The monkeypox case was reported in Broward County and appears to be linked to international travel, officials said.
Cases of the infectious disease have also been reported in New York City and Massachusetts.
President Joe Biden addressed the growing international outbreak on Sunday, warning “everybody” should be concerned about the spread of monkeypox.
“They haven’t told me the level of exposure yet but it is something that everybody should be concerned about,” he told reporters on Air Force One while travelling from South Korea to Japan.
Mr Biden said that US officials are “working on it hard to figure out what we do and what vaccine if any might be available for it”.
His comments contradicted advice from the Centers for Disease Control and Prevention (CDC) who have urged calm.
More than 190 people across 16 countries are believed to have contracted the disease, which spreads from primates to humans.
The US is rushing to secure up to 13 million vaccine doses.
Biotech company Bavarian Nordic revealed this week that the US government had placed an $119m order for its Jynneos vaccine.
A further $180m is also ready and waiting for more vaccines if or when needed, altogether enabling the country to procure 13 million doses for the American people.
On Wednesday, a Massachusetts man who had just returned from Canada became the first suspected US case of the infectious disease.
A New York City patient became the first confirmed case in the US on Thursday. Their tests have been sent to the CDC for further evaluation.
The CDC has warned doctors and public health officials to look out for patients who may have monkeypox symptoms and report those cases to the CDC.
CDC official Jennifer McQuiston emphasised that the public “should not be concerned” about the sudden rise in infections of the rare illness and that the risk remains low.
Experts say early symptoms are similar to the flu, with fevers and chills common. But that can develop into a painful rash that spreads across the face, body, soles of feet and the inside of the mouth.
