At least six people were injured and hospitalized Sunday morning as several possible tornadoes struck the Oklahoma City area after authorities issued tornado warnings, including one for the University of Oklahoma's Norman campus.

One of the twisters is suspected of landing in Oklahoma City, where most of the injuries reported Sunday occurred. Police and firefighters said the six injured people were being treated at hospitals for non-life-threatening injuries.

Several buildings were damaged, power lines and trees were downed and gas lines were disrupted as the possible tornadoes swept through the area for four hours starting around 11 p.m. Saturday, said Nolan Meister, a meteorologist with the National Weather Service (NWS). in Norman, Oklahoma, ABC News said Sunday morning.

“We estimate there were at least six tornadoes and possibly as many as 12,” Meister said, adding that the severe weather also caused flash flooding and large hail in the area.

He said the NWS has confirmed “some” of the tornadoes and is working to confirm the others.

A possible tornado hit the community of Choctaw, about 17 miles (27 kilometers) east of Oklahoma City, around 1 a.m., according to Choctaw police.

The suspected tornado swept through Railhead Estates in Choctaw, causing “extensive damage” to homes and prompting firefighters and police to go door-to-door checking on residents, authorities said in a statement.

According to police, several people were slightly injured in the incident.

“There is significant damage to homes in the area,” the police statement said. “We have opened the Choctaw Elementary School gymnasium to anyone who needs a temporary place to rest and shelter.”

The nearby town of Harrah was also damaged, according to Choctaw police, adding that people sought shelter at a local casino.

Images of damage also emerged Sunday in Newcastle, about 14 miles south of Oklahoma City.

Meister told ABC News that around 9 a.m. ET, all tornado warnings in the area were lifted. But Meister said the NWS is forecasting more severe weather, including thunderstorms, for the Oklahoma City area Sunday afternoon.

Emergency tornado warnings issued Sunday included one that prompted students and staff at the University of Oklahoma's Norman campus to seek shelter, officials said.

The warning was posted on the school's official X account at 1:22 a.m. At 1:55 a.m. and 2:02 a.m. the school issued additional warnings

“Seek shelter in the building you are in NOW,” the first message said. “Go to the lowest floor/interior.”

At that time, the NWS said it was monitoring for tornadoes across central and eastern Oklahoma early Sunday. A small area of ​​northwest Texas was also under a watch, the agency's Storm Prediction Center said in an urgent update at 1:40 a.m

The center said about 15 minutes later that it had seen several “individual supercells” that had “matured within the open warm sector over OK.”

“A tornado watch means conditions are favorable for tornadoes and severe thunderstorms in and near the observation area,” the center said. “People in these areas should remain vigilant for threatening weather conditions and watch for subsequent statements and possible warnings.”