Boston Mayor Marty Walsh on Thursday urged city residents to remain cautious over the Memorial Day weekend, avoiding cookouts and beaches to limit the spread of COVID-19.

He said those who want to celebrate veterans should do so by decorating their homes with flags and “other patriotic symbols’’ — and staying safe. He invited those interest to attend remote events that will be held to honor veterans.

“We are facing a tough enemy, we are making sacrifices,’’ he said. “We have role models in our fallen heroes who can inspire us right now.”

Walsh spoke during a press conference outside Boston City Hall where he released the latest grim coronavirus tally — 12,143 residents who have tested positive, 591 people have passed away from COVID-19.

He spoke three days after Gov. Charlie Baker announced a four-part plan to re-open the state following months of lockdown. The first phase includes opening, with restrictions, of hair salons, offices and houses of worship. Walsh reiterated earlier comments that he likely will be more cautious. He said the number of active cases has been declining, but that doesn’t mean people should be less careful.

“There should be no play dates still, there should be no visiting elderly or high risk individuals and also no sports,” he said.

Walsh said he’s particularly concerned about people letting down their guard heading into a holiday weekend with sunny weather expected. He said about 10 percent of all Bostonians have been COVID positive or had the antibodies, leaving the vast majority of people still at risk.

“There is a lot of room for the virus to be spread,’’ he said.

City officials are working on official guidance for businesses looking to open, he said, which should be completed over the weekend. But a return to normal will not be anytime soon.

"I am going to be encouraging as many people work from home as possible,” he said, before putting on his face mask and walking away.