Detroit reported its lowest daily case increase Friday of COVID-19 since March as Mayor Mike Duggan praised the efforts of Detroiters to social distance and mitigate the spread of the disease.

Two parts of the Detroit Health Department website reported new case increases of 19 and 60. It's not yet clear which figure is accurate and the city health department did not immediately clarify, but either figure represents the lowest increase in more than a month. On March 13, Detroit's total case increase was 57.

The case increase reported Friday brings the city total to 7,406, while the 34 new deaths reported bring Detroit’s total fatalities to 572.

"What the people of Detroit, in the last few weeks, have done in social distancing in knocking down this virus" is stunning, Duggan said during a press conference Friday.

"When we go back and look at the numbers, I think you're going to find that Detroit went up as fast as anybody and it went down as fast as anybody," he said.

Among the numbers reported Friday, about 62% of the cases involve African Americans while 77% of the deaths occurred among blacks.

Roughly 55% of the cases occurred among women while 55% of the deaths occurred among men.

According to zip code data released by the city Friday, the northwest corner of Detroit appears to have the heaviest case load.

The 48235 zip code, which includes the Detroit Medical Center's hard-hit Sinai-Grace Hospital, has the highest concentration of cases with 724 people testing positive while the neighboring 48219 zip code has the second highest, with 547 cases.

Duggan said more work needed to be done to study and address the reasons Detroit was hit so hard and the distrust black residents might have of the medical community.

"I spent nine years running the Detroit Medical Center and overcoming the racial gap in this country on health care is a challenge, it's something everyone who worked there worked on every single day," he said.

Two weeks ago, Duggan said, some Detroiters couldn't find a doctor to get a prescription for a test, but since then the city has identified 30 offices willing to take on new patients.

"Even if you don't have money, they'll take you right now," he said. "It's phenomenal the way the medical community has stepped up."

Duggan also announced that starting Monday, the city would offer testing for essential employees throughout the city at the former Michigan State Fairgrounds.

Businesses will be prioritized, he said, with employees in industries such as food services, where the virus could spread easily, at the top of the list.

"They aren't able to shelter in place," Duggan said. "They have to be out and interact. And starting Monday, I want every business in the city of Detroit to know that if you have to be open because you're essential, that we will test all of your employees."

The first positive case was reported in the city just over a month ago.

Duggan this week cautioned observers the state's reporting system for COVID-19 deaths might be unreliable at times because some of the daily numbers reflect "older cases that we finally caught up on."

It was not immediately clear whether Friday's death total included individuals who had died outside of the previous 24 hours, said Vicki Winn, a spokeswoman for the Detroit Health Department.

eleblanc@detroitnews.com