Long Beach on Tuesday reported 10 additional deaths from COVID-19—by far the highest number in a single day—but officials cautioned that the number was inflated by delays in reporting.

“The new data does not suggest a spike or surge in fatalities for the City of Long Beach,” according to a statement from the city. The 10 fatalities actually occurred over the span of May 13 to 18, the statement said.

But even spread out over those five days, the string of deaths marks a significant uptick in fatal cases.

In the past few weeks, Long Beach has sometimes gone days at a time without reporting a new death. And there have only been a handful of times that Long Beach reported three deaths in a day—the highest single-day number until today.

Long Beach officials said the 10 deaths weren’t revealed publicly until today because of “delayed weekend reporting from Long Beach Memorial Medical Center,” and one fatality where COVID-19 wasn’t diagnosed until after death.

“The City is dependent on the information that is received from other jurisdictions and hospitals,” Long Beach officials said in a statement. “This notification process can often take several days to complete.”

Long Beach has also been plagued by delays in reporting COVID-19 test results. Last week, the city began reporting spikes in its number of positive cases but said some of those cases date back to April 1.

Mayor Robert Garcia said last week that officials are still trying to sort out exactly when those tests were performed.

City officials reported 57 new positive tests for the coronavirus Tuesday, bringing the total number of confirmed cases to 1,362.

Long Beach’s total number of hospitalizations also remained higher than the average over the past few months with 58 on Tuesday.

The city’s nursing homes continue to be the hardest-hit by coronavirus, accounting for 48 of the city’s 62 fatalities.