LOS ANGELES -- Los Angeles County, the most populous county in the United States, set a new record of COVID-19 hospitalizations Sunday for a fourth consecutive day with over 10,000 new cases.

According to the latest data released by the Los Angeles County Department of Public Health, 4,009 people are currently hospitalized with 21 percent in the ICU. Sunday's figure broke the record set on Saturday with 3,850 patients in hospital.

Meanwhile, the department reported 12,731 new cases and 29 deaths in the previous 24 hours, bringing the tally of new infections to 525,486 and 8,298 related deaths.

On Dec 7, when hospitalizations were 2,988, Los Angeles County Health Director Barbara Ferrer warned that the figure could climb to 4,000 within two weeks, which came in just six days.

Haig Aintablian, a senior physician with the University of California Los Angeles Emergency Medicine program, was quoted by the local KTLA news channel as saying that the current situation was the worst he had seen for hospital systems in the county and local hospitals were "almost at a critical point."

As the first shipments of the Pfizer COVID-19 vaccine left Michigan early Sunday for 145 distribution centers in the US and was scheduled to arrived Los Angeles County on Monday, local authorities repeatedly warned residents to wear mask.

"1 in 100 people in LA County are currently infected with COVID-19. Don't gather and wear your face covering whenever you are outside your house," the Department of Public Health tweeted Sunday night.