Hong Kong reported 1,347 new daily COVID-19 infections on Sunday, down from the previous day’s record, but the spread, with 2,000 more suspected cases, threatens the city’s overstretched healthcare system, authorities said.

The surge in coronavirus cases, the biggest test yet for Hong Kong’s “dynamic zero-COVID” strategy, comes a day after the government said China would help the city with testing, treatment and quarantine capacity.

Following the death of a four-year-old who had tested preliminary positive for the disease this week, the government said late on Sunday that children from the age of three would be eligible for vaccinations from Feb. 15.