SULPHUR, Okla. (AP) — Tornadoes killed four people in Oklahoma and left thousands without power Sunday after a destructive outbreak of severe weather flattened buildings in the heart of one rural town and injured at least 100 people across the state.

More than 20,000 people remained without electricity after tornadoes began late Saturday night. The destruction was extensive in Sulphur, a town of about 5,000 people, where a tornado crumpled many downtown buildings, tossed cars and buses and sheared the roofs off houses across a 15-block radius.

“You just can’t believe the destruction,” Oklahoma Gov. Kevin Stitt said during a visit to the hard-hit town. “It seems like every business downtown has been destroyed.”

Stitt said about 30 people were injured alone in Sulphur, including some who were in a bar as the tornado struck. Hospitals across the state reported about 100 injuries, including people apparently cut or struck by debris or hurt from falls, according to the Oklahoma Department of Emergency Management.

White House officials said President Joe Biden spoke to Gov. Stitt on Sunday and offered the full support of the federal government.

The deadly weather in Oklahoma added to the dozens of reported tornadoes that wreaked havoc in the nation’s midsection since Friday. On Sunday, authorities in Iowa said a man injured during a tornado that hit the town of Minden on Friday had died, according to local reports.

Authorities said the tornado in Sulphur began in a city park before barreling through the downtown, flipping cars and ripping the roofs and walls off of brick buildings. Windows and doors were blown out of structures that remained standing.

“How do you rebuild it? This is complete devastation,” said Kelly Trussell, a lifelong Sulphur resident as she surveyed the damage. “It is crazy, you want to help but where do you start?”

Carolyn Goodman traveled to Sulphur from the nearby town of Ada in search of her former sister-in-law, who Goodman said was at a local bar before just before the tornado hit the area. Stitt said one of the victims was found inside a bar but authorities had not yet identified those killed.

“The bar was destroyed,” Goodman said. “I know they probably won’t find her alive … but I hope she is still alive.”

Farther north, a tornado near the town of Holdenville killed two people and damaged or destroyed more than a dozen homes, according to the Hughes County Emergency Medical Service. Another person was killed along Interstate 35 near the southern Oklahoma city of Marietta, state officials said.

Heavy rains that swept into Oklahoma with the tornadoes also caused dangerous flooding and water rescues. Outside Sulphur, rising lake levels shut down the Chickasaw National Recreation Area, where the storms wiped out a pedestrian bridge.

Stitt issued an executive order Sunday declaring a state of emergency in 12 counties due to the fallout from the severe weather.

At the Sulphur High School gym, where families took cover from the storm, Jackalyn Wright said she and her family heard what sounded like a helicopter as the tornado touched down over them.

Chad Smith, 43, said people ran into the gym as the wind picked up. The rain started coming faster and the doors slammed shut. “Just give me a beer and a lawn chair and I will sit outside and watch it,” Smith said. Instead, he took cover.

Residents in other states were also digging out from storm damage. A tornado in suburban Omaha, Nebraska, demolished homes and businesses Saturday as it moved for miles through farmland and into subdivisions, then slammed an Iowa town.

The tornado damage began Friday afternoon near Lincoln, Nebraska. An industrial building in Lancaster County was hit, causing it to collapse with 70 people inside. Several were trapped, but everyone was evacuated, and the three injuries were not life-threatening, authorities said.

One or possibly two tornadoes then spent around an hour creeping toward Omaha, leaving behind damage consistent with an EF3 twister, with winds of 135 to 165 mph (217 to 265 kph), said Chris Franks, a meteorologist in the National Weather Service’s Omaha office.

Nebraska Gov. Jim Pillen and Iowa Gov. Kim Reynolds spent Saturday touring the damage and arranging for assistance for the damaged communities. Formal damage assessments are still underway, but the states plan to seek federal help.