Singapore’s health ministry confirmed 942 more coronavirus infections on Saturday, a new daily record, the vast majority of which are among migrant workers living in dormitories.

Authorities have managed to mitigate the spread of the virus and the COVID-19 respiratory disease it causes among Singapore’s citizens by rigorous contact tracing and surveillance, earning praise from the World Health Organization.

The Ministry of Health reported just 14 cases among Singaporeans and permanent residents on Saturday.

But the disease is spreading rapidly within the large migrant worker community, highlighting what rights groups say is a weak link in containment efforts. Authorities have ramped up testing for the disease in the dormitories.

Saturday’s new cases takes the total in the city-state, which is under a partial lockdown, to 5,992. It has reported 11 deaths from the disease.