WASHINGTON - US President Joe Biden approved early Sunday a disaster declaration for the southern state of Mississippi after deadly tornadoes.

Biden ordered federal aid to supplement recovery efforts in the areas affected by "severe storms, straight-line winds, and tornadoes" from Friday to Saturday.

"Twenty-five Mississippians were killed overnight due to this severe weather," the Mississippi Emergency Management Agency said in a statement, warning that a large portion of the state has the potential to see severe storms on Sunday evening.

"Expect damaging wind gusts. Tornadoes cannot be ruled out," the agency tweeted.