The governor of Texas has temporarily halted the state's reopening as COVID-19 infections and hospitalisations surged and the US set a new record for a one-day increase in cases.
Texas, which has been at the forefront of efforts to reopen devastated economies shut down in the face of the coronavirus pandemic, has seen one of the biggest jumps in new cases, reporting more than 6000 in a single day on Monday.
"This temporary pause will help our state corral the spread until we can safely enter the next phase of opening our state for business," Governor Greg Abbott, a two-term Republican, said in a statement.
Texas has also set record hospitalisations for 13 days in a row. Abbott has suspended elective surgeries in the Houston, Dallas, Austin and San Antonio areas to free up hospital bed space.
Texas' rising numbers are part of a nationwide resurgence in states that were spared the brunt of the initial outbreak or moved early to lift restrictions on residents and businesses.
Cases rose across the United States by at least 39,818 on Thursday, the largest one-day increase of the pandemic.
More than 36,000 new US cases were recorded on Wednesday, a few hundred shy of the record 36,426 on April 24.
Also reporting record rises in cases this week were Alabama, Arizona, California, Florida, Idaho, Mississippi, Missouri, Nevada, Oklahoma, South Carolina and Wyoming.
While some of the increased numbers of cases can be attributed to more testing, the percentage of positive results is also climbing.
The Trump administration has tried to soften nationwide concerns about the pandemic even as a dozen or so states see worrisome increases.
"We're working aggressively with states and local leaders in this situation but it's important for the American people to know this is a localised situation," US Health and Human Services Secretary Alex Azar told Fox News in an interview. "The counties that are in hotspots are three per cent of American counties."
Government experts believe more than 20 million Americans could have contracted the coronavirus, 10 times more than official counts, indicating many people without symptoms have or have had the disease, senior administration officials said.
The focus of the pandemic has moved to the US west and south, including more sparsely populated rural areas, from the early epicentre around New York.
In California, Governor Gavin Newsom, a Democrat, declared a budget emergency due to the pandemic.
Nearly 5350 people there tested positive for the coronavirus in the past 24 hours, fewer than Wednesday's record of 7149. But the number of Californians becoming very ill continued to rise, using about 34 per cent of the available intensive care beds in the state, up from 29 per cent on Wednesday.
New York, New Jersey and Connecticut on Wednesday ordered travellers coming from eight mostly southern states to self-quarantine for two weeks on arrival.
New York Governor Andrew Cuomo said on Thursday that New York reached a new milestone as the number of people hospitalised with COVID-19 fell to 996, the first time since March 18 the number fell below 1000.
Cuomo, a Democrat who has been sharply critical of Donald Trump's handling of the pandemic, during an interview on CNN appeared to blame the president and other Republicans for the surges in other states.
"You played politics with this virus and you lost," Cuomo said on CNN.
Australian Associated Press