More than a month ago, President Donald Trump stood in the Rose Garden alongside the CEOs of Target, Walmart, CVS and Walgreens and announced a new public-private partnership to make drive-through tests available in store parking lots across the country.

Five weeks later, that effort has been slow to ramp up, as governors and business leaders clamor to find a way to provide more widespread testing so parts of the economy can reopen.

Minneapolis-based Target's only drive-through testing site is outside its store in Chula Vista, Calif., with partner University of California, San Diego.

Walmart has opened nine sites, with plans for 20 by the end of the month. Walgreens has opened nine of 15 sites planned; CVS has opened five.

Some stumbling blocks have been the same challenges that health care practitioners face nationwide: access to testing supplies and personal protective equipment (PPE). Also, the partnership is a loosely coordinated one with much of the work being left up to retailers to hash out along with state and local officials.

"It's part of a consistent pattern of [the Trump administration] rolling out announcements with great fanfare that don't in reality measure up," said Jeremy Konyndyk, a senior policy fellow at the Center for Global Development.

Retailers say they are committed to the effort but say it has taken time to coordinate and then use pilot sites to finalize plans. After seeing what worked, they have adjusted their operations and are now beginning to expand them.

At the federal level, the U.S. Department of Health and Human Services says it continues to work with the pharmacies and retail companies to accelerate testing.

"We are using data to locate sites in counties that are undertested and socially vulnerable," the department said in a statement.

It added that the retail partners are responsible for providing the end-to-end testing process including online registration, staffing, supplies and lab testing. The companies must also provide the tests at no cost to Americans, the federal agency said.

Last week, Trump said states are better suited to handle the logistics of such testing sites than the federal government.

"We're not going to be running a parking lot in Arkansas," he said, referencing the home state of Walmart. "The states are much better equipped to do it."

A White House spokesman did not respond to a request to comment.

Target said it remains committed to the testing effort where needed and is working with local and federal officials to identify locations.

But the coordination can be tricky. It had been working with local officials, the Federal Emergency Management Agency and the National Guard on opening a testing site in the coming week outside one of its stores in Baltimore. The city ultimately decided to move it to another location.

One of Target's challenges is that it doesn't have its own in-house health expertise since it sold its in-store pharmacies to CVS several years ago. Target CEO Brian Cornell told reporters late last month that the company will rely on CVS for technical knowledge and staffing.

"We're certainly supportive of using our space, but we'd be partnering with our friends at CVS to help bring this to life," he said.

He noted that setting up such sites can be complex in terms of equipment and operations.

"As we understand more from the pilots, we'll certainly be supportive of providing the property and the space for the expansion," he said. "But it's a new space for all of us, and we're working together."

In the meantime, Target has posted prominent signs in the front windows of its stores that say "This store is NOT a CDC testing center" to deter people who may be seeking testing from coming inside the store.

About a week after the Rose Garden announcement, CVS opened its first testing site in a store parking lot in Massachusetts. "We learned a lot from our first pilot test site," said Joseph Goode, a CVS spokesman.

CVS is now using the recently federally approved Abbott ID NOW test, which gives results within 15 minutes. CVS also decided to put its next few locations in larger and more accessible parking lots away from its stores — for example, a college parking garage in Atlanta.

CVS can now test 1,000 people a day at each of these newer sites. "We're delivering on our commitment to helping increase the frequency and efficiency of testing," said Goode, noting that CVS has tested more than 35,000 people to date.

Walmart plans to have 20 sites in more than 10 states open by the end of this month.

"We have learned a lot from our initial sites and working to help expand testing in areas of need as quickly as possible," Marilee McInnis, a Walmart spokesman, said in an e-mail.

Walgreens says will be able to test up to 3,000 people a day at the sites it is opening in Arizona, Florida, Illinois, Kentucky, Louisiana, Tennessee and Texas.

The exact locations of some of the sites are still being finalized, but are aimed at hot spots with escalating rates of COVID-19 cases.

As is the case with many of these store parking lot tests, patients have to fill out an online assessment tool to see if they meet federal criteria to qualify for a test and have to pre-register in advance to schedule an appointment.

None of these retailer-based drive-through sites have opened yet in Minnesota. However, some health systems in the state are offering drive-up or curbside testing by appointment, often for high priority groups.

Meanwhile, the University of Minnesota and the Mayo Clinic are ramping up their in-state testing capacity. Gov. Tim Walz has said he hopes to be able to conduct 5,000 tests a day in Minnesota as the state eases up on restrictions in its stay-at-home order, which is scheduled to expire May 4.

Staff writer Joe Carlson contributed to this report.