As the number of confirmed COVID-19 cases continues to grow at an expanding rate, Gov. Charlie Baker on Sunday tried to put the numbers into a larger context, stressing that the higher figures are in part a result of increased testing in Massachusetts.

On Saturday, the Department of Public Health announced there are 525 cases in Massachusetts, an increase of 112 over the day before. The update was the third straight day with the largest daily jump since the first case was detected on Feb. 1 and came hours before the state confirmed its second death attributable to the coronavirus.

Baker, who spoke to reporters after participating in a service at the Morning Star Baptist Church, said testing also increased 50 percent each of the past two days. The total number of cases, he said, is "going to climb."

"The reason that number is going to climb is because we're testing more," Baker said. "That's not necessarily a bad thing. And by the way, people are recovering at the same time that new people are coming on."

Through Saturday afternoon, the state public health laboratory had tested 3,031 patients since the start of the outbreak, while commercial labs had tested more than 2,100. The administration aims to have capacity to test 3,500 patients per day by early this week.

Increasing the availability and frequency of tests is "one of the key elements of success" in fighting the virus's spread, Baker said.

"I fully expect that testing is going to go up in leaps and bounds based on changes in the federal standards and availability of additional test capacity here in Massachusetts," he said. "I've said now for five or six days that as we test more, we're going to find more people who are infected, and that's then going to lead to a lot more aggressive approaches to deal with tracing and isolation."

Every county in Massachusetts now has at least one confirmed case as of Sunday.

The islands had been the last areas in the state without detected infection, but one case emerged on Martha's Vineyard on Saturday and Nantucket Cottage Hospital reported its first positive test on Sunday.

Nantucket officials issued a shelter-in-place order for the island Sunday, effective from Monday at 5 p.m. through April 6, according to an NBC Boston report. Baker has resisted calls for a similar statewide order.

Asked about Nantucket's first case, Baker said officials from both islands have reported that non-permanent residents are flowing in to stay at their vacation homes in attempts to avoid the virus — a practice the governor said creates risks.

"We would prefer they not do that and that they stay on the mainland and don't create additional issues for both of those islands at a point in time when they don't have the same level of service capacity in place they would typically have in the summer," he said.

Gov. Charlie Baker sits in the pews of Morning Star Baptist Church before a prayer service gets underway. [Photo: Chris Van Buskirk/SHNS]Talks are ongoing between the Baker administration and both the Federal Emergency Management Agency and the U.S. Army Corps of Engineers about using vacant college dormitories, closed nursing facilities and other spaces to create additional medical treatment capacity for the surge in cases that public health officials expect.

Baker said Sunday that his staff would offer suggested sites "over the next few days" that could be converted. Once a location was selected, he said, the federal agencies could set up field hospitals in two to three weeks with differences depending on the nature of the underlying facility.

"Between dormitories and hotels and decommissioned hospital beds and nursing homes, we have a lot of different kinds of capacity that can be brought up relatively quickly," Baker said. "One of the things the (coronavirus) command center is working on with folks in the health care community is what the actual requirement would look like, where it would need to be in terms of the commonwealth generally, and what kind of capacity it would be."

Another key element of the state's response will be acquiring personal protective equipment for those on the front lines, and Baker — who earlier this week told President Donald Trump that states were being outbid by the federal government — said governors across the country are "chasing PPE as hard as we possibly can."

The governor decided to keep pre-existing plans to visit Morning Star on Sunday despite the outbreak, as he did with an appearance at an empty temple on Friday night.

Baker said since he was first elected, he has tried to make two to four visits per month to churches, synagogues, mosques and cathedrals in Massachusetts to "check in" and, when given the opportunity, to speak.

"Honestly, it troubles me that at a point in time when so many people are appropriately concerned and worried about the present and the future and all the issues associated with COVID-19, we can't really give them the chance to come sit shoulder to shoulder to shoulder as they normally would on a Friday or a Saturday or a Sunday with people they've been sitting shoulder to shoulder with for years to find that sense of hope and security and comfort that comes with being part of a community like this," he said.