Bloomberg said no one should generalize about any group, but authorities must respond to the threat of criminal activity.
There have been three more cases of measles confirmed in New York City. The new cases bring the number of people who have come down with the disease since January to 13.
The Nassau County Health Department says someone exposed to the contagious disease was at Winthrop University Hospital sometime between last Friday and Monday.
Officials say two young women from France who were not vaccinated against measles attended a party at the New Jersey restaurant.
Health officials say a 9-month-old baby infected with measles may have exposed others last month at a Long Island department store.