The US government has confirmed more than 1,800 cases of Zika in the US and Colombia.
The first confirmed case of Zika infection was reported in Miami on Sunday, where at least 12 people have tested positive.
The virus has not been confirmed in Colombia.
“We’ve had reports that more than 40% of all cases have been in the Miami area,” Miami Mayor Tomas Regalado told reporters.
“The virus is spreading.”
Regalado said the city has taken measures to keep people safe, including limiting outdoor activities and limiting people to four people per bedroom, adding that he did not know if the virus was spreading further in the city.
The mayor also said the health department has received more than 3,800 confirmed cases in Miami and has sent a team of health officials to Colombia.
He added that the city is monitoring the situation in the South American country.