A coronavirus outbreak is ravaging a hospital in Shanghai for older adults, underscoring the difficulties officials have had in containing infections even as the city imposed a 10-day staggered lockdown.

Two orderlies at the Shanghai Donghai Elderly Care Hospital said in interviews that the coronavirus was spreading widely among the mostly older patients in the facility, and that people had died on each of the past three days. The two, who declined to be named for fear of losing their jobs, said that on a recent night they had been asked to carry a body into a room where other bodies were being stored.

The two said they did not know how the people had died, but said that many had been infected with Covid, and that there was a shortage of tests and other resources. The New York Times also spoke with a Shanghai resident, Chen Jielei, who said her 81-year-old mother tested positive for Covid-19 in the hospital.

The situation points to an unfolding health care crisis in China’s largest city, and exposes a vulnerable group in the country’s otherwise highly effective Covid-19 strategy: the elderly.