New York state has recorded its highest number of COVID-19 deaths in 24 hours, Governor Andrew Cuomo said on Tuesday, adding though that hospitalizations appeared to be "plateauing."

Cuomo said 731 people succumbed to the new coronavirus on Monday, bringing the state's total death toll to 5,489. The previous single-day record was 630, set on Friday. New York has borne the brunt of America's deadly coronavirus pandemic, accounting for around half the number of deaths across the country.

COVID-19 has killed more than 11,000 people in the United States, according to a running tally by Johns Hopkins University. Cuomo said New York appeared be nearing the peak of its pandemic, with a three-day average of hospitalizations down.

He added that intensive care admissions and intubations had also declined. "We're projecting that we're reaching a plateau in the number of hospitalizations," Cuomo told reporters.

He said social distancing was working, urging New Yorkers to continue to stay indoors unless absolutely necessary. "I know it's hard but we have to keep doing it," Cuomo implored.

On Monday, the governor extended a shutdown until near the end of the month, ordering schools and non-essential businesses to remain closed until April 29.

New York City Mayor Bill de Blasio said it was "too early to draw any definite conclusions" about whether the situation was improving in the Big Apple. "I want to really make sure none of us in public life tell you we have turned a corner until we are absolutely certain," he told reporters.

Elsewhere, a crew member of the military hospital ship USNS Comfort tested positive for the virus, a navy spokesperson told AFP. The vessel arrived in New York last month to relieve the burden on hospitals overwhelmed with COVID-19 patients.

"The crew member is isolated from patients and other crew members. There is no impact to Comfort's mission, and this will not affect the ability for Comfort to receive patients," said the spokesperson.