SULPHUR, Okla. (AP) - Small towns in Oklahoma began a long cleanup Monday after tornadoes flattened homes and buildings and killed four people, including an infant, widening a destructive outbreak of severe weather across the middle of the U.S.

Punishing storms that began late Saturday in Oklahoma injured at least 100 people, damaged a rural hospital, washed out roads and knocked out power to more than 40,000 customers at one point, state officials said. Tornadoes on Friday in Iowa and Nebraska also caused wide destruction and were blamed for one death.

The destruction was extensive in Sulphur, a town of about 5,000 people south of Oklahoma City, 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 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, according to the Oklahoma Department of Emergency Management. An infant was among those killed, Hughes County Emergency Management Director Mike Dockrey told Oklahoma television station KOCO.

The deadly weather in Oklahoma added to the dozens of reported tornadoes that have wreaked havoc in the nation’s midsection since Friday. Another death was reported Sunday in Iowa, where officials in Pottawattamie County said a man critically injured during a tornado Friday had died.

In Oklahoma, 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 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?”

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.

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, said Chris Franks, a meteorologist in the National Weather Service.