The U.S. government is using smartphone location data from the mobile ad industry to track people's movements amid the coronavirus outbreak, according to a Wall Street Journal report.

Local governments and the Centers for Disease Control and Prevention have received the anonymized data about people in areas of "geographic interest," with the aim being to create a portal of geolocation information for 500 cities across the country.

The information will be used to learn how well people are complying with stay-at-home orders, according to WSJ. Citing an example, the report says researchers discovered large numbers of people were gathering in a New York City park, which led them to notify local authorities.

Even though the data is anonymized, WSJ says that privacy advocates want "strong legal safeguards" to limit how it can be used, in order to prevent its use for other purposes. Cellular carriers told the news outlet they have not been asked by the government to provide location data.

The development follows reports of other countries using cellphone data to monitor citizens and see if they are complying with curbs on movement to defeat the viral outbreak.

European mobile carriers have reportedly been sharing data with health authorities in Italy, Germany and Austria, while at the same time respecting Europe's privacy laws. Earlier this month, Israel passed emergency measures that allow security agencies to track the smartphone data of people with suspected COVID-19 and find others they may have come into contact with.