US officials have issued a new advisory that says pregnant women should not travel to the so-called Zika “transmission area” in Florida.
The Centres for Disease Control and Prevention also said that pregnant women who live there should take steps to prevent mosquito bites and sexual spread of the virus.
The CDC issued the advisory after Florida Governor Rick Scott said there are 10 new infections of the Zika virus likely transmitted by mosquitoes, bringing the total in the state to 14.
The new cases are clustered in the same square-mile neighbourhood in Miami-Dade County identified last week.
Florida health officials say they believe active transmissions of Zika are occurring only in that area.
The CDC says men and women who have visited this area since June 15 should wait at least eight weeks before trying to conceive.
Because Zika infection has been found to linger in sperm for months, men with Zika symptoms should wait at least six months before trying to have a baby with their partner.