KANSAS CITY, Mo. (AP) — Thunderstorms and tornadoes tore across the nation's heartland Saturday evening, killing at least 11 people, mangling buildings and trapping people in the rubble of their homes in areas still reeling from other recent bouts with severe weather.

A twister killed at least six people in the northeastern Oklahoma town of Picher on Saturday and left widespread destruction, authorities said.

The death toll could go higher, said Oklahoma Emergency Management spokeswoman Michelann Ooten. The tornado caused major damage in a 20-block area, she said.

"I know they are going through the rubble, trying to find people missing," she said. "There are numerous injuries."

First responders were working to free people trapped in the rubble, the department said.

At least five people died in southwestern Missouri after the storms plowed through, the National Weather Service said. Three people died after a tornado hit near Seneca in Newton County, said meteorologist Bill Davis.