ISTANBUL, Dec 30 (Reuters) - Turkey recorded 39,681 new COVID-19 cases on Thursday, the highest number of daily infections since April 28, as Health Minister Fahrettin Koca warned about the growing prevalence of the Omicron variant. The number of daily cases has doubled in the last week and Koca said the situation required people to be much more careful than they have been in the past. Turkey also recorded 139 deaths as a result of the virus on Thursday, down from 142 a day earlier.