As Massachusetts begins the first phase of gradually reopening the economy, Boston Mayor Marty Walsh expressed on Tuesday some unease with a few of the early steps being taken.

The state's plan will allow Boston businesses that begin to reopen to bring back 25 percent of their workforce on June 1. Walsh, however, thinks that number may be too high.

"I'm personally not comfortable with the 25 number, to be quite honest with you, and we're looking at it now," Walsh said. "I think 25 percent the first day is too much."

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Boston has unique challenges as a densely populated city of 700,000 that doubles on a typical workday with the influx of employees commuting, the mayor said.

“We want to help employers create guidelines,” he said, pointing to shift scheduling, physical spacing and ventilation. “Reopening must only happen in a way that safe for you, your workers and your customers.”

Walsh called on employers not to force any employees to come into offices if they are able to work from home.

While Gov. Baker’s plan, which he announced yesterday, would allow places of worship to reopen this weekend, Walsh specifically cautioned elderly people to wait to attend services and asked religious leaders to convey this same message.

“Speak directly to seniors,” he said. “We know you are missing your places of worship, but please wait. Guide your elderly parishioners to safety first.”

Walsh said he is especially worried about small business owners who can’t pay their rents or mortgages and might simply fold and never reopen. But many business owners are also concerned about the health risks of reopening, Walsh added.

“If you don’t feel comfortable opening, we will back your decision and make our services open to you,” he said. “I want to assure all the people of Boston, we are committed to your health, safety and wellbeing as long as it takes. And we will not take steps that put anyone at risk.”

More than 12,000 Boston residents have been infected with COVID-19 and 588 have died from the disease.

Walsh said last week’s coronavirus testing in Boston found just under 14 percent of people positive, the lowest rate the city has seen during the pandemic.