New clusters of Chinese coronavirus emerged in Seoul and Daegu this week, sparking fears of a resurgence in cases in South Korea.

Gyeonggi Province — which surrounds Seoul, South Korea’s capital and most populous city — reported 15 new cases of the virus on Wednesday, raising the total number in the province to 277. Daegu, a southeastern city at the epicenter of the nation’s outbreak, reported 70 new infections at a nursing home this week.

Some have praised South Korea recently for its seemingly successful efforts to curb the country’s aggressive initial outbreak, citing a reported slowdown in new cases along with increased testing. However, experts local to Asia question the data used to support this praise, suggesting the reported numbers may not depict the full picture. These experts warn that what appears to be a slowdown in new cases may simply be a delay in the reporting. Some point to the ongoing mass testing of 200,000 members of the controversial religious sect Shincheonji, linked to about 60 percent of the Chinese coronavirus cases in South Korea, as an example.

Joong Sik Eom, a professor of infectious diseases at Gachon University in Seongnam, told South Korea’s Hankyoreh 21:

If you exlude Shincheonji, the situation looks similar to other countries … If you look at the emergence of regional clusters of 1,500-2,000 people and the number of cases, we are heading toward a situation like that of France. If you take out Shincheonji and look at the remaining data, it has been steadily rising from the first patient.

As reported Wednesday by the South China Morning Post (SCMP), Ben Cowling, an infectious diseases expert at the University of Hong Kong also cautioned against calling South Korea a success story just yet. “[T]here will always be a risk of a surge in cases resulting from silent transmission,” Cowling said. “Infection spread by cases that have not been detected in the community.”

Also speaking to the SCMP Wednesday, Hsu Li Yang, an associate professor at Saw Swee Hock School of Public Health at the National University of Singapore, said, “…we should expect, that clusters of cases will inevitably pop up in large countries as the pandemic progresses, particularly where social distancing interventions have not been extreme, [such] as in the strategy employed by South Korea.”

The latest Chinese coronavirus clusters to emerge in Seoul and Daegu seem to support these experts in their claims that South Korea’s outbreak may not actually be under control.