WASHINGTON (AP) - The government's top infectious disease expert says the U.S. still lacks critical testing and other procedures needed to begin reopening the nation's economy, adding a dose of caution to increasingly optimistic projections from the White House.

Dr. Anthony Fauci told The Associated Press that easing off strict social-distancing rules would be on a "rolling" basis around the country.

He says localities should be prepared to see new COVID-19 cases when that happens and act quickly to contain them.

Asked about May 1, an increasingly discussed target date, Fauci called that possible but "a bit overly optimistic."

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President Donald Trump is suggesting that governors' objections to his claim of absolute authority over when to lift guidelines aimed at fighting the coronavirus are tantamount to insurrection. In a tweet Tuesday,  he invoked the movie "Mutiny on the Bounty" and said, "A good old fashioned  mutiny every now and then is an exciting and invigorating thing to watch,  especially when the mutineers need so much from the Captain."

Democratic and Republican governors sounded alarm about a federal power grab a day after Trump asserted he had the ultimate say on when and how to reopen the economy after weeks of tough social distancing guidelines.