President Donald Trump has claimed "total" power to lift the nationwide coronavirus lockdown, contradicting governors and legal experts.
"The president of the United States calls the shots," Mr Trump said during a combative press conference in which he feuded with reporters.
But the US Constitution says the states maintain public order and safety.
Ten states on the US East and West coasts are planning to lift their strict stay-at-home orders.
The US is the global epicentre of the coronavirus pandemic with 554,684 confirmed cases and 23,608 deaths.