Four people were reported killed in Oklahoma, where the twisters gained strength, and four others died further north in the Midwestern state of Michigan.

The Branch County Sheriff's Office said a tornado touched down near Union City in southern Michigan on Friday, killing three people and injuring 12.

About 50 miles (80 kilometers) west, officials in Cass County said one person was killed and "several injuries" were reported after a tornado hit the area.

"Our thoughts are with those who have lost family, friends, and property during this incident," the Branch County Sheriff's Office said in a statement.

Authorities in Cass County said a number of trees had fallen onto roads and buildings, and more than 500 people were reported to be without power.

"Emergency Management personnel will be conducting damage assessments in the affected area as required by the State of Michigan," the local sheriff's office said.

Michigan Governor Gretchen Whitmer said Friday evening she was activating a state emergency operations center "to coordinate an all-hands-on-deck response to severe weather in southwestern Michigan."

In Oklahoma, the extreme weather led to fourth deaths late Thursday and Friday, and people were waking up Saturday to scenes of destruction and loss in several towns across the state.

"Severe weather struck Major County last night and tragically claimed the lives of a mother and daughter," Oklahoma Governor Kevin Stitt posted on X.

Okmulgee County Sheriff Eddy Rice said in a statement that two people died in a tornado that hit the town of Beggs on Friday night.