NEW YORK - The number of confirmed COVID-19 cases in the United States topped 550 as of midnight Sunday, adding more than 200 cases over the weekend, according to the Johns Hopkins Center for Systems Science and Engineering.

Meanwhile, 21 fatalities occurred in three states, including 18 in Seattle area of Washington state, two in Florida and one in California.

Washington D.C. reported its first confirmed case on Saturday. Mayor Muriel Bowser said the patient is a local resident in his 50s who showed symptoms in late February and was admitted into a hospital on March 5.

The man had no international travel history, nor was he known to have contacted any confirmed case, said the mayor.

Also, a US Marine assigned to Fort Belvoir of Virginia, near Washington D.C., tested positive on Saturday for COVID-19, said Jonathan Hoffman, assistant to the US Secretary of Defense for Public Affairs, in a statement.

"The Marine recently returned from overseas where he was on official business," tweeted Hoffman on Saturday, adding that Secretary of Defense Mark Esper and the White House have been briefed.

One day after New York governor declared a state of emergency, the number of confirmed coronavirus cases in the Empire State surged to 105 on Sunday, 16 more than the day before, according to Governor Andrew Cuomo.

Cuomo called on the US federal government to expedite their approval of private labs and automated and manual testing to expand New York State's testing capacity, according to an announcement from the governor's press office.

He also encouraged New Yorkers to work from home, telecommute and avoid densely populated spaces whenever possible to help contain the spread of the virus.

According to the state's health authorities, 93 of the confirmed cases are outside of New York City, most of which are clustered in Westchester County.

Cuomo said the state "mobilized quickly," but the federal government has been "slow off the mark and they continue to be slow."

"That's unacceptable. We need them to approve these private labs today so we can stay ahead of this evolving situation," said the governor.

Getting these additional facilities online will "ensure we have more facts that will help keep people calm," he added.

Meanwhile on the West Coast, the 35th Los Angeles Marathon was held on Sunday as scheduled with a record 27,150 entrants, despite the fact that the Los Angeles County declared a state of emergency over the disease earlier this week.

Los Angeles City Council Member Mike Bonin on Friday questioned the decision to run the race, saying on Twitter that "This is a big popular event, but I remain concerned & don't think it's worth the risk."

However, Los Angeles Mayor Eric Garcetti insisted that there was no reason to cancel the marathon or other events so far.

Entries from runners with a mailing address in China, Italy, South Korea and Iran were deferred to the 2021 race, according to Murphy Reinschreiber, chief operating officer of the McCourt Foundation, one of the organizers.