A Pentagon memo written for Secretary of Defense Mark Esper warned of a "long path ahead" as the United States continues to battle the coronavirus pandemic that has killed nearly 100,000 Americans.
Military news website Task & Purpose obtained a copy of the memo, which warned of a potential "resurgence" of the virus.
"We have a long path ahead, with the real possibility of a resurgence of COVID-19," the document reads.
"Therefore, we must now re-focus our attention on resuming critical missions, increasing levels of activity, and making necessary preparations should a significant resurgence of COVID-19 occur later this year."
Kenneth Rapuano, the assistant secretary of defense for homeland defense and global security, wrote the memo, according to Task & Purpose. He argued that even with more testing, the virus could come back strong later this year when flu season begins.
"All indications suggest we will be operating in a globally-persistent COVID-19 environment in the months ahead," Rapuano wrote. "This will likely continue until there is wide-scale immunity, through immunization, and some immunity post-recovery from the virus."
Cases will crop up "in clusters" during the flu season, according to the document, and testing "will not provide 100% assurance of the absence" of SARS-CoV-2, the virus that causes COVID-19.
Thousands of new cases are reported every day, but states have begun to reopen their economies with more than 36 million Americans having filed for unemployment benefits since mid-March when virus-related closures began.