A tornado has ripped through a FedEx depot in Michigan, trapping 50 people inside the building, officials say.
The twister hit in Portage, eight miles (13km) south of Kalamazoo on Tuesday, damaging multiple buildings. There were no reports of injuries at this point.
More than 32,600 customers were without electricity, according to the PowerOutages.US website.
The National Weather Service meanwhile issued its first "tornado emergency" for Michigan, the highest alert level.
Taylor Koopman, of the Kalamazoo County Administrator's office, told MLive.com that 50 people were trapped in the partially destroyed FedEx facility.
Collapsed wires and debris must be removed in order to reach the group, she said, adding that it remained an "active scene"
A tornado emergency, the most severe type of tornado alert issued by the service, tells people that a tornado is imminent or has already been spotted in the area.
A lower "tornado watch" remains in effect for several counties in southeast Michigan, as well as parts of Indiana and Kentucky.
At least seven homes were reported "destroyed" in Branch County, Michigan, one emergency management official told US media.