SEOUL, South Korea (AP) — South Korea has reported 50 new cases of COVID-19 as officials began requiring nightclubs, karaoke rooms and gyms to register their customers with smartphone QR codes so they could be easily located when needed.

The figures from the Korea Centers for Disease Control and Prevention on Wednesday brought national totals to 11,902 cases and 276 deaths. At least 41 of the cases were reported from the Seoul metropolitan area, where officials have struggled to trace transmissions linked to entertainment venues, church gatherings and low-income workers who couldn’t afford to stay home.

Since late May, the country has been reporting around 30 to 50 new cases per day, a resurgence that has threatened to erase some of the hard-won gains against the virus as people begin to ease on distancing.

The nationwide requirement of QR codes at “high-risk” venues come after a week-long trial run in the cities of Seoul, Incheon and Daejeon, where some 300 businesses used an app developed by internet company Naver to collect the information of some 6,000 customers. The government is also encouraging churches, libraries, hospitals and movie theaters to voluntarily adopt the technology.

South Korea has aggressively mobilized technological tools to trace contacts and enforce quarantines, with an infectious disease law strengthened after a 2015 outbreak of a different coronavirus, Middle East Respiratory Syndrome or MERS, allowing authorities quick access to cellphone data, credit-card records and surveillance camera footage.

But critics say privacy is being sacrificed for epidemiological gains and that it’s excessive to preemptively collect personal details through smartphone QR codes when there are no clear grounds to consider the individuals as potential virus carriers.

Prime Minster Chung Sye-kyun during a virus meeting on Wednesday tried to downplay the privacy concerns, saying that the information collected through the apps will be destroyed after a certain period.