New York City has become the new epicenter of the coronavirus pandemic, and as the number of cases continues to increase each day, so has the number of 911 calls. In fact, the number of emergency calls on some days has exceeded the number of calls received on September 11, 2001.

Carl Gandolfo, recording secretary for Local 2507, a union that represents FDNY EMTs, paramedics and fire inspectors, said there's been a dramatic increase in the number of 911 calls since March 21.

"On a normal day we do anywhere from 4,000 - 4,200 calls a day," Gandolfo told CBS News via email. "Since March 21st we have been well over 5,500 calls a day." And some days the number has been even higher than that.

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Gandolfo said between last Tuesday, March 24, and Sunday, March 29, the call volume exceeded 6,500 a day. The number of calls peaked at over 7,000 two days in a row — with 7,100 calls on March 26 and 7,082 calls on March 27.

That's nearly a 30% increase over the number of calls received on the day of the September 11 attacks.

"The call volume on 9/11 hit 5,500 on the day, and we had an average of 3,000 calls a day back then," Gandolfo said. Local 2507 President Oren Barzilay also confirmed this number to CBS News.

On Sunday, FDNY EMS members responded to 5,956 medical calls, the FDNY said on Twitter. The FDNY is urging New Yorkers to only call 911 "during a real emergency." The department has been posting this message on Twitter daily.

Yesterday, March 29, FDNY EMS members responded to 5,956 medical calls. FDNY urges New Yorkers to only call 911 during a real emergency. For coronavirus info visit https://t.co/xkV3QFsjaZ and text COVID to 692-692 for updates from@NotifyNYC pic.twitter.com/DI0vJihUib — FDNY (@FDNY) March 30, 2020

CBS News has reached out to the FDNY for more information.

The death toll from the virus climbed 1,000 in New York state on Sunday, less than a month after the first known infection in the state. Most of those deaths have occurred in just the past few days.

With an expected surge in the number of coronavirus patients in the city, New York and federal emergency officials have been busy preparing new field hospitals, including one that transformed the Javits Convention Center in Manhattan into a massive medical facility.

On Monday, the U.S. Navy hospital ship the USNS Comfort, which was also sent to New York City after 9/11, arrived in the city to provide an additional 1,000 beds. The floating hospital be used to treat non-coronavirus patients so hospitals can focus their resources on people with COVID-19, the disease caused by the virus.