By Melanie Evans, Joseph Walker and Stephanie Armour

As the pandemic pushes U.S. hospitals in the South and West near capacity, the urgent need for available beds has stranded patients in emergency rooms, scrambled ambulances and forced patients to relocate hundreds of miles to relieve overcrowded wards.

In Arizona, hospitals are using a statewide transfer center to move 30 to 50 patients between hospitals each day, according to the director of the state's Department of Health Services. In Florida, hospital giant HCA Healthcare Inc. isn't accepting patients transferred from other overflowing hospitals. In Houston, the daily hunt for empty beds has left critically ill patients to wait hours or days in emergency rooms for vacancies.

A dozen Houston-area hospitals had a combined 273 patients holding in emergency rooms for an empty bed Tuesday, including about 40 in need of intensive care, said Darrell Pile, chief executive of the Southeast Texas Regional Advisory Council, which tracks bed availability and helps hospitals coordinate transfers. "This disaster beats all disasters," he said.

The sustained surge in hospitalizations there and in other cities like Phoenix and Miami is straining the response effort, as the need for beds is running up against shortages of staff -- and in some cases space. Hospitalizations elsewhere in the U.S. have intensified demand for health-care workers, he said. The public's noncompliance with mask or social-distancing guidelines further allows the virus to spread, he said.

"What we're facing has gotten much worse than anyone ever imagined and much worse than anyone could ever prepare for," Mr. Pile said. "The public has to do its part."

Hospitals in Arizona reported nearly 3,500 coronavirus patients Tuesday, a figure that has climbed steadily after the state reopened its economy and coronavirus cases surged. Texas in late June moved to scale back its reopening, halting some nonessential surgeries in certain counties and rolling back bar openings, as hospital intensive care units grew full. But occupancy rates continue to climb in Texas hot spots.

The surge in patients and rising numbers of deaths in some U.S. communities follow the increase in cases that has happened alongside efforts to restart local economies.

Across the U.S., more than 3.43 million people have been infected, and 136,466 have died, according to data compiled by Johns Hopkins University. States like Florida and Arizona have hit new highs in recent days, and now other states, including Tennessee, West Virginia, Oklahoma and South Carolina, have seen new coronavirus cases jump 20% or more from a week ago.

A clear picture of hospital strain is limited, however, by uneven public reporting across states and hospitals and ad hoc efforts by federal officials to collect data since the pandemic began.

Federal officials on a call with reporters Wednesday defended a decision to have hospitals report data on Covid-19 cases, critical supplies and staff to the U.S. Department of Health and Human Services rather than the Centers for Disease Control and Prevention.

Critics fear the move would enable the Trump administration to politicize hospital virus data by impeding access to or sharing of information.

"Rather than strengthening the public health data system to improve hospital reporting, the administration has chosen to hand data to an unproven, commercial entity, reporting to political appointees, not scientific experts," Dr. Tom Frieden, who ran the CDC during the Obama administration, tweeted Wednesday. The data collection will be overseen by a private contractor, TeleTracking.

Michael Caputo, a spokesman for HHS, said the CDC system is no longer adequate for monitoring hospital information and that the agency can't keep up with the pandemic.

CDC Director Robert Redfield told reporters Wednesday that no one is taking access or data away from CDC.

He said the White House coronavirus task force had for months urged improvements.

Hospital surge response differs across states, which have taken varied roles in tracking patient capacity and transfers. States also have taken mixed approaches to mandates to halt nonessential hospital services.

In New York, where the pandemic overwhelmed hospitals early on, there were fewer than 1,000 coronavirus patients in hospitals Tuesday with roughly 12,700 available hospital beds. This is down from a high on April 12, when nearly 19,000 Covid-19 patients were hospitalized across the state and hospitals were ordered to increase their bed capacity by 50%.

Hospitals saw revenue plunge as most halted some surgeries in late March and April, either voluntarily or under state orders, then rapidly ramped back up as states eased restrictions.

Arizona requires hospitals that have capacity to accept patients from its state transfer coordination center, said Cara Christ, head of Arizona's Department of Health Services. That prevents any one hospital system from bearing a disproportionate share of the surge, she said. Some hospitals in the state have voluntarily halted nonessential surgery. The state requires hospitals to suspend the procedures when total occupancy levels exceed 80%, a spokeswoman said.

In Florida, HCA Healthcare said last week it would limit scheduled surgeries and cancel those that could safely be postponed.

To preserve hospital capacity in Texas, Gov. Greg Abbott in late June halted surgery across four counties, including Harris County, which is home to Houston. Since then, intensive-care occupancy across the county's hospitals has increased to 98% from 92%, SETRAC data show. Mr. Abbott later expanded the number of counties subject to the order.

Creating more intensive-care beds will be challenging with acute staffing challenges, Mr. Pile said. "This virus has gone on so long and has consumed staff from all parts of the state," Mr. Pile said. "There are no longer enough staff to put a patient in all of those beds."

Memorial Hermann Health System continued to add beds with its Houston-area hospitals near capacity, a spokeswoman said. It has received 60 nurses deployed by the state to provide relief and hired additional staff through temporary agencies.

The Texas Department of State Health Services as of July 8 had sent roughly 1,200 health-care workers to hospitals and had another 576 on standby, said agency spokesman Chris Van Deusen.

Some hospitals say they can't add any more beds. Harris Health System, which operates two public hospitals in Houston, is at its maximum, said Charlie McMurray-Horton, its associate administrator for clinical integration and transformation.

Harris's hospitals have struggled to find empty beds elsewhere for 10 to 30 patients who need transfers each day. That has left some patients stranded in the emergency room until a vacancy appears and forced its hospitals to turn away ambulances.

More capacity for Harris Health's hospitals depends on other Houston-area hospitals adding beds to accept more transfers, Ms. McMurray-Horton said. "We are intertwined," she said. "Wherever there is an increase in beds, it helps out the community."

The Texas Department of State Health Services generally doesn't coordinate patient transfers, which is done between hospitals or with aid of regional coalitions, Mr. Van Deusen said.

In Laredo, Texas, a surge in new Covid-19 infections was overwhelming the city's hospitals, which were running out of inpatient beds, medical equipment and health-care workers to treat patients, said Victor Treviño, Laredo's Health Authority.

"We're in a crisis mode," said Dr. Treviño, 72 years old. "In my 40 years of practice I've never seen anything like this."

At one city hospital, patients seeking care in the emergency room were overflowing into the hallways last week, and ambulances idle outside and wait for space to be cleared to bring in new patients, Dr. Treviño said. The city's hospitals converted more beds into space for Covid-19 patients and health-care workers deployed by the state have added capacity, but it likely won't last, he said.

Hospitals don't have enough high-flow oxygen devices, a less-invasive method than ventilators to provide oxygen support to patients with respiratory problems, Dr. Treviño said.

"Intubations are not ideal because the outcome of the patient is worse if he's intubated," he said. "We would prefer the high-flow oxygen therapy, but where are the machines? They're not here."

The city is out of the antiviral drug remdesivir made by Gilead Sciences Inc. used to treat Covid-19 patients, the second time it has run out. The city received 200 vials of the drug on July 4 -- or enough to treat about 33 patients at the most common dosage -- after it ran out of the drug the prior week, Dr. Treviño said.

"We're putting out fires constantly, constantly, constantly," he said.

--Melanie Grayce West contributed to this article.

Write to Melanie Evans at Melanie.Evans@wsj.com, Joseph Walker at joseph.walker@wsj.com and Stephanie Armour at stephanie.armour@wsj.com