The U.S. Centers for Disease Control warned pregnant women Monday not to travel to an area in the southeastern state of Florida where new cases of Zika virus infections have been identified.

Florida officials have discovered ten more cases of the Zika virus, increasing the total there to 14 and prompting Governor Rick Scott to ask for federal help to fight the spread of the virus.

“A team is being deployed by the CDC in short order so that we will be able to work with Governor Scott’s team on the ground in South Florida,” White House spokesman Eric Schultz told reporters on Monday.

Scott said all known cases of Zika in Florida were caused locally by mosquitos.

State health officials believe the spread of the Zika virus is limited to a square mile area in Miami-Dade County, just north of downtown Miami. The area is rapidly gentrifying and has numerous construction sites where standing water can collect and serve as a breeding area for mosquitos.

In addition to the travel warning aimed at pregnant women, the CDC said pregnant women in the Miami area should make every effort to avoid mosquito bites.

 Officials identified six of the new cases by conducting door-to-door community surveys.   

On Friday, officials announced four cases of the Zika virus, believed to be the first cases contracted from mosquitos within the 50 U.S. states.

More than 1,650 people in the mainland U.S. have contracted the virus in recent months, nearly all while traveling in other countries.

 U.S. officials have said they do not expect broad outbreaks like those in Brazil and in some other Latin American countries.

Aggressive mosquito control efforts in Florida were announced on Friday but the CDC said mosquito control efforts are not working as well as expected.

Health officials have reminded the public that most people with Zika don't know they are sick and that infection during pregnancy can cause babies to develop birth defects.