Updated at 1:16 p.m.

Massachusetts Gov. Charlie Baker Wednesday announced what he is calling a “Stop the Spread” testing initiative, geared toward tamping down the coronavirus in eight Bay State cities.

Chelsea, Everett, Fall River, Lowell, Lawrence, Lynn, Marlborough and New Bedford have all seen more COVID-19 cases than the statewide average and a decrease in testing volume since April. At a press conference Wednesday, the governor said residents of these cities comprise only nine percent of the state's population but in the past two weeks have made up nearly 30 percent of the state's positive tests.

In the last two weeks, he added, the state has had an average positive test rate of about two percent. The average positive test rate in these cities is eight percent.

“Increased testing within these communities will help to identify new cases of COVID-19 and help stop community transmission," he said. “By boosting testing in these communities, we can more effectively drive contact tracing and support there.”

The free testing program begins July 10 and will run through the middle of August.

At the press conference Baker also strongly encouraged people to continue wearing face coverings in public and said that low positive test rate among participants in the state's recent widespread protests demonstrates this precaution's effectiveness.

“We tested 16,000 people who were involved in large gatherings, primarily the demonstrations that took place over a two-week period of time,” Baker said. “The vast majority of the people who participated in those demonstrations and marches wore masks, and the positive test rate coming out of that was 1.27 percent.”