The White House coronavirus task force warned in a report to states this week that a rapid increase in cases this winter could be the result of a domestic variation of the virus, separate from the U.K. variant.

“This fall/winter surge has been at nearly twice the rate of rise of cases as the spring and summer surges,” the task force wrote in its weekly report, which was obtained by The Hill.

“This acceleration suggests there may be a USA variant that has evolved here, in addition to the UK variant that is already spreading in our communities and may be 50% more transmissible,” the report states.

“Aggressive mitigation must be used to match a more aggressive virus; without uniform implementation of effective face masking (two or three ply and well-fitting) and strict social distancing, epidemics could quickly worsen as these variants spread and become predominant,” it continued.

The report does not say there is hard evidence of a new strain of the virus, but instead that cases are rising so rapidly that it may indicate a more contagious strain in the U.S. The United Kingdom has been hit hard by a new, more contagious, strain that was discovered there and has already been detected in several U.S. states.

“This isn't actually the fact that we've discovered a different variant here in the United States,” former Food and Drug Administration Commissioner Scott Gottlieb said Friday on CNBC when asked about the report.

“It's largely pattern recognition where we're fitting our curve on top of the UK curve, and right now the trajectory of what's ensuing here in the United States looks a lot like what has ensued in the United Kingdom,” he added. 

The U.K. strain of the virus is so far thought to be more contagious but not more deadly. It's also not thought to be resistant to vaccines, though research is ongoing. 

The U.S. has been regularly setting new records over the past several weeks for daily infections and deaths from the virus as the country struggles to get the pandemic under control.

Johns Hopkins University reported there were 4,085 coronavirus deaths in the U.S. on Thursday, marking the first time the country had surpassed 4,000 deaths in a single day.

The rollout of approved vaccines from Pfizer and Moderna has been marred by confusion over distribution as officials attempt to prioritize who should get the shots first and how to quickly administer them without letting doses go to waste.

So far, about 6 million out of roughly 21 million doses distributed have been administered, according to the Centers for Disease Control and Prevention (CDC). The Trump administration is encouraging states to expand the categories of people eligible for the vaccine doses as a way to speed up the process and ensure tight criteria are not slowing it down. 

The task force in its report this week urged states not to delay the vaccination of those over the age of 65 or who people at higher risk of serious complications from the virus.

“Messaging must be focused on proactive testing of those under 40 to prevent asymptomatic silent spread to their household members and on a call to action for immediate testing and rapid infusion of monoclonal antibodies for those at risk for severe disease,” the report states. “Every hospital should have outpatient infusion sites immediately available to save lives.”

When asked about the report on Friday, the CDC said there is a "strong possibility" there are variants in the United States, but it will take time to determine if there is a single variant fueling the surge like in the U.K., and no such variant has been identified so far.

"Based on scientific understanding of viruses, it is highly likely there are many variants evolving simultaneously across the globe," a CDC spokesperson said. "Additionally, there is a strong possibility there are variants in the United States; however, it could [take] weeks or months to identify if there is a single variant of the virus that causes COVID-19 fueling the surge in the United States similar to the surge in the United Kingdom."

"Researchers have been monitoring U.S. strains since the pandemic began, including 5,700 samples collected in November and December," the spokesperson added. "To date, neither researchers nor analysts at CDC have seen the emergence of a particular variant in the United States as has been seen with the emergence of B.1.1.7 in the United Kingdom or B.1.351 in South Africa."