Cases of COVID-19 are surging across the country, including in major U.S. cities that have mandated masks and vaccinations amid the spread of the omicron variant.

New York City averaged 36,856 reported cases per day as of Monday, which is a 517% increase from the average two weeks ago, according to government data compiled by The New York Times.

NYC MAYOR DE BLASIO ANNOUNCES COVID-19 VACCINE MANDATE FOR PRIVATE SECTOR WORKERS

Weeks before his term expired in December, former New York City Mayor Bill de Blasio announced that effective Dec. 14, the city government would require proof of vaccination for indoor dining, fitness and entertainment from children as young as 5 years old. Beginning Dec. 27, New Yorkers aged 12 and older were required to show proof of two vaccine doses, except for those who have received the Johnson & Johnson vaccine.

New York state, which before had peaked at 251,000 daily cases last January, has been seeing an average of about 400,000 cases daily in 2022, according to The New York Times.

Former Mayor of New York City Bill de Blasio speaks during the opening of a vaccination center for Broadway workers in Times Square on April 12, 2021 in New York City. (Photo by Noam Galai/Getty Images)

Former Mayor of New York City Bill de Blasio speaks during the opening of a vaccination center for Broadway workers in Times Square on April 12, 2021 in New York City. (Photo by Noam Galai/Getty Images) (Noam Galai/Getty Images)

Washington, D.C., which reinstated an indoor mask mandate on Dec. 21, has also continued to see a surge of COVID-19. According to data compiled by The New York Times that was updated Monday, the nation's capital is averaging 2,103 cases per day, which is a 485% increase over the past two weeks and the highest one-week spike of the entire pandemic.

The high number of test positivity rates further indicate that the number of cases in the nation's capital is being "significantly undercounted."

Washington, D.C. (iStock)

Washington, D.C. (iStock)

Effective Jan. 15, District residents 12 and older must provide proof of at least one dose of vaccine at restaurants, bars, nightclubs, indoor entertainment facilities, gyms and indoor meeting establishments. By Feb. 15, proof of two doses of vaccine will be required, except for the Johnson & Johnson vaccine.

NEW YORK, FLORIDA SHATTER SINGLE-DAY RECORDS FOR COVID-19 CASES

Other major cities that have seen large spikes of COVID-19 despite mask or vaccine mandates include Chicago, Boston and Los Angeles.

The average daily number of COVID-19 cases in Illinois, which has a statewide mask mandate, surpassed 16,000 for the first time last week, with Chicago boasting the highest infection rate.

Starting Monday, anyone in Chicago aged 5 and over is required to show proof of full vaccination at any public place that serves food and drinks, including bars, restaurants, sports stadiums, entertainment venues, and more. Anyone aged 16 and older will have to show an ID that matches the name on the vaccination record. 

CHICAGO, ILLINOIS - NOVEMBER 12: Chicago Mayor Lori Lightfoot gets a COVID-19 booster vaccine at Michele Clark High School on Nov. 12, 2021 in Chicago, Ill.

CHICAGO, ILLINOIS - NOVEMBER 12: Chicago Mayor Lori Lightfoot gets a COVID-19 booster vaccine at Michele Clark High School on Nov. 12, 2021 in Chicago, Ill. (Photo by Scott Olson/Getty Images)

Boston, which has had mask mandate since August, saw a large surge reflected in the numbers that have recently come out of Suffolk County, which has seen a 245% increase in positive cases over the past two weeks. Like Washington, D.C., Boston residents are required to have two doses of vaccine to participate in most public venues by Feb. 15.

CLICK HERE TO GET THE FOX NEWS APP

With 17,894 cases per day, Los Angeles County has likewise seen a huge spike that reflects an 644% increase from the average two weeks ago. Los Angeles County reimposed a mask mandate in July.