WASHINGTON - US President Joe Biden on Wednesday criticized Republican governors in southern states of Texas and Mississippi over their decisions to reverse mask mandates and other COVID-19 safety policies, calling these actions "Neanderthal thinking".

"I think it's a big mistake. Look, I hope everybody's realized by now, these masks make a difference. We are on the cusp of being able to fundamentally change the nature of this disease because of the way in which we're able to get vaccines in people's arms," Biden told reporters from the White House.

"The last thing -- the last thing we need is Neanderthal thinking that in the meantime, everything's fine, take off your mask, forget it. It still matters," said the president.

Though the Centers for Disease Control and Prevention (CDC) warned of a fourth resurgence in coronavirus cases earlier this week, Mississippi Governor Tate Reeves said on Tuesday that all state regulations would be lifted starting on Wednesday.

"Starting tomorrow, we are lifting all of our county mask mandates and businesses will be able to operate at full capacity without any state-imposed rules. Our hospitalizations and case numbers have plummeted, and the vaccine is being rapidly distributed. It is time!" he tweeted.

Also on Tuesday, Texas Governor Greg Abbott announced his state would revoke all state-imposed coronavirus regulations starting on March 10, citing lower case counts and the surge of vaccine accessibility.