(CNN) -- Refrigerated trailers to be used as makeshift morgues hummed outside two hospitals on Thursday as New York City deals with the surging death count in the epicenter of the nation's coronavirus pandemic.
The last time New York took such drastic measures was after the terrorist attacks of September 11, 2001, when the city medical examiner's office was tasked with identifying tens of thousands of body parts from the 2,753 people killed in the World Trade Center collapse.
The makeshift morgues signal the historic challenge posed by the national health crisis.
At least 281 people have died from Covid-19 across the city, Mayor Bill De Blasio said Thursday. There are 21,873 confirmed cases of the virus.
New York state, where 385 people have died from the virus, has more than 37,000 of the nation's more than 80,000 coronavirus cases.
The US death toll from coronavirus has topped 1,100.
At least 13 patients had died from Covid-19 over a 24-hour period this week at Elmhurst Hospital in Queens -- where the medical examiner's office stationed a refrigerated trailer, according to agency spokeswoman Aja Worthy-Davis.
Another four deaths were reported at the hospital in the last 24 hours, said Mitch Katz, president and chief executive officer of NYC Health + Hospitals, the largest municipal health system in the country.
Trailers and white tents were also set up outside New York Bellevue Hospital Center, which is adjacent to the medical examiner's building.
Davis noted the refrigerated trucks are not specifically for coronavirus cases. They're intended to help alleviate the morgue space at hospitals if needed. The trailers will be used if the hospital morgues reach capacity.
"We're in a public health crisis, and the city has declared a state of emergency," the Office of the Chief Medical Examiner (OCME) said in a statement.
"As part of that declaration, agencies like OCME have enacted emergency contingency plans to help prepare for every possible outcome."
The trucks are part of a city plan to prepare for the potential surge of bodies from the coronavirus pandemic, Worthy-Davis said.
The trailers outside the two hospitals are property of the city Office of Emergency Management.
The medical examiner has another 45 large trucks at its disposal. No OCME trailers have been deployed. Those trailers were purchased recently in response to a disaster plan that called for a "significant stocking up," Davis said.
"We have a pretty large capacity compared to hospitals," said Davis, adding that the trucks plus the mobile tents increase the morgue capacity to 3,500 to 3,600 bodies.
The city has a capacity of 900 bodies in morgues in all five boroughs, along with expanded capacity at certain other locations.
OCME workers are taking precautions in handling bodies, sanitizing the outside of the body bags and the surfaces that the bodies touched, Davis said.
The Federal Emergency Management Agency has said it received a request from New York and other states for assistance with mortuary operations. Hawaii and North Carolina have made similar requests.
The agency is reviewing the requests, according to FEMA.
New York City also has longstanding contracts with companies to provide refrigerated trucks but that plan is not active, officials said. Those trucks would likely be stationed at various locations, including makeshift hospitals such as the one set up at the Javits Convention Center.
CNN's Elizabeth Joseph, Priscilla Alvarez and Elizabeth Hartfield contributed to this report.