It would be "incredibly irresponsible" to send everyone back to work at the same time, Gov. Charlie Baker said Wednesday, pushing back against critics who have accused him of moving too slowly to restart the state's economy as he simultaneously tries to steer the state through the COVID-19 crisis.

The governor also resisted calls for him to tease out details of his reopening strategy before Monday, urging patience as some legislators and industries, like restaurants, are clamoring to be told what businesses will be on the initial list to reopen and what might be expected of them.

"I would love to be able to open everything up tomorrow. That would be an incredibly irresponsible thing to do," Baker said.

Baker addressed questions about his phased-in reopening plan from the parking lot of a community health center in Fall River where he traveled to tour one of the state's drive-through testing sites. The Stanley Street Treatment and Resources Center was one of the 18 community health centers that the administration teamed with Quest Diagnostics to provide supplies and support for testing.

Baker said residents have sacrificed too much over the past nine weeks to risk a second breakout of the virus because of growing impatience. His message of caution has been reinforced in recent days by officials like Attorney General Maura Healey, who said on the radio Tuesday that a "true patriot" would follow the governor's instructions.

"People have gone through a tremendous amount of dislocation and discomfort and lost wages and a whole bunch of other things over the course of the past 60 days to get to get to the point where the virus has been contained enough and reduced enough that we can actually start to reopen the economy," Baker said. "The last thing we're going to do is reopen it in a way that fires that virus up again."

Testing, Baker said, will increasingly become a critical part of returning to work and more normal daily life for residents, and he said the state has plans to significantly ramp up testing in the coming months.

The state has so far tested more than 401,000 of its roughly 6.9 million residents, and at its peak tested 15,652 people in a single day on May 3. That volume of testing puts Massachusetts among the top five states, and even top five countries, for per capita testing, the governor said.

But Massachusetts could be doing more. Baker said labs have the capacity to test 30,000 a samples a day, which will allow the state to greatly expand access over the summer.

"Testing remains, obviously, a critically important pillar in our battle against COVID-19, both now and into the future, especially as we begin to plan the reopening process," Baker said.

Baker noted that the Department of Public Health issued new guidance on Tuesday recommending that anyone with symptoms of COVID-19, even if they are mild, be tested, along with anyone who has had close contact with a case of coronavirus. He acknowleged that the inability of people with mild symptoms to get tested early in the pandemic had been a source of "frustration and, in some cases, fear of the unknown."

"It will not only help us understand where the infections are, but it will also help us help people isolate, participate in the tracing program and return to their normal lives faster. As we consider our reopening strategy, we view this as a critical component of getting toward a new normal that will help us navigate our daily lives with the presence of COVID-19," he said.

Some public officials and industries, however, think the governor isn't allowing them to return to their lives and livelihoods fast enough.

Three Republican lawmakers on Tuesday called on the governor to immediately provide more clarity on his plan for reopening, and to put his trust in business owners to figure out how to safely return to work. Restaurants are among the industries clamoring to be told what they might need to do to reopen beginning next week.

The Massachusetts Fiscal Alliance wrote a letter to every member of the Legislature on Wednesday complaining of Baker's reluctance to share details of his plan before May 18.

"Millions of residents of the Commonwealth followed the Governor's lock down order, now it's time for the Governor to listen to the millions of Massachusetts small business owners and workers who want to safely reopen. Every job is essential and every day is essential. The Governor needs to be clear and transparent with the specifics of his plan and not delay another day," said Paul Craney, spokesman for the alliance.

The experience of the shutdown has been very different for white collar workers who continue to work from home and be paid and blue collar workers who have lost their jobs, Craney said.

The Greater Boston Chamber of Commerce had hoped Baker would announce his phased reopening plan by Friday, May 8, to give employers and workers at least 10 days to prepare for a potential reawakening of activity.

Baker has insisted that his plan will focus first on reopening businesses that have limited face-to-face interactions with customers.

"I want this to be done in a deliberate way, and you don't do something in a deliberate way when you start leaking it out and issuing it out before you actually release the report. I don't want the starting gun, so called, to go off today or tomorrow. I want it to go off on Monday, and I want it to go off in a targeted and phased way, period," Baker said.

The rate of positive test results for COVID-19 and the declining number of patients hospitalized with the disease have shown progress in the state's fight against the virus over the past several days. The Department of Public Health reported 870 new cases on Tuesday with a positive test rate of 13 percent, and only 33 new deaths.

But Baker said that some hospitals are still operating under surge plans that took advantage of extra space and staff to accommodate an influx of COVID-19 patients requiring beds. There are still more than 3,000 patients hospitalized with COVID-19 in Massachusetts and almost 1,000 in intensive care, he said.

"This is not a virus to be trifled with or disrespected and I think it's important for everybody to understand that," Baker said.