Federal health officials on Monday urged pregnant women to stay away from a Miami neighborhood where they have discovered additional cases of Zika infection — apparently the first time the Centers for Disease Control and Prevention has advised people not to travel to a place in the continental United States.

Florida officials said the number of Zika cases caused by local mosquitoes had risen to 14 from the four announced on Friday: 12 men and two women. They declined to say whether either woman was pregnant. All of the cases have been in one neighborhood.

Health officials said they still did not expect the number of local cases to grow into anything comparable to the epidemic that has raged across Latin America in recent months.

The 10 newly identified patients were most likely infected weeks ago, as early as mid-June, the officials said.