Health officials say two babies have been born with Zika-related defects in California.
The California Department of Public Health said Thursday the infants were born to infected mothers who spent time in countries where the virus is circulating.
Authorities said one of the mothers returned to her home country with the baby. The other remains in California.
Nineteen other pregnant women in California infected with Zika are being monitored.
Nationwide, 13 babies have been born with Zika-related birth defects, according to the federal Centers for Disease Control and Prevention.
The CDC has advised pregnant women not to travel to Zika-affected parts of Latin America and the Caribbean and the Wynwood neighborhood in Miami.
Florida is the only U.S. state so far that has reported homegrown Zika transmission by mosquitoes.