At least 11 people were injured early Sunday and about 100 homes were damaged or destroyed when several tornado invaded the Oklahoma City area.

Officials issued tornado warnings Sunday, including one for the University of Oklahoma’s Norman campus.

One of the twisters is believed to have landed directly in Oklahoma City, where most of the injuries occurred. Police and firefighters said the injured were being treated at hospitals for non-life-threatening injuries.

The Oklahoma City Fire Department said Sunday it successfully rescued two adults who were trapped inside an overturned mobile home. In addition, he said firefighters responded to people stuck in their vehicles due to flash flood conditions.

As of Sunday afternoon, no deaths had been reported.

However, Oklahoma City officials reported that 39 structures were destroyed, another 43 sustained major damage, and 54 structures sustained minor damage.

Officials said damage assessments were ongoing, and Gov. Kevin Stitt issued a six-county emergency declaration late Sunday.

In addition to damaged or destroyed structures, power lines were downed, trees were uprooted and gas lines were snapped when possible twisters tore through the area over a four-hour period beginning around 11 p.m. Saturday, Nolan Meister , meteorologist for National. The National Weather Service (NWS) in Norman, Oklahoma, told ABC News on Sunday.

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

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

A possible tornado touched down in the Choctaw community, about 17 miles east of Oklahoma City, at about 1 a.m., according to Choctaw Police Department.

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

Several people were reported to have suffered minor injuries in the incident, police said.

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

The nearby town of Harrah’s also suffered damage, according to the Choctaw Police Department, which added that people were sheltering at a local casino.

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

Meister told ABC News that around 9 a.m., all tornado warnings in the area were lifted.

However, he said more severe weather is headed for the Oklahoma City area. The NWS issued several tornado warnings for the Oklahoma City area Sunday afternoon and said thunderstorms are also expected.

The NWS said Sunday afternoon that a twister that touched down in southeast Oklahoma City was rated an EF3 on the Enhanced Fujita Scale, meaning it had wind speeds of 136-165 mph. Another tornado that hit Comanche in Stephens County was upgraded as at least an EF2 tornado with wind speeds of 111-135 mph, officials said.

The NWS has forecast more severe weather through Sunday for the Oklahoma City area.

Among the emergency tornado warnings issued Sunday was one that prompted students and staff at the University of Oklahoma’s Norman campus to shelter in place, officials said.

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

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

At the time, NWS said was tracking tornadoes in central and eastern Oklahoma. A small area of ​​northwest Texas was also under watch, the agency’s Storm Prediction Center said an urgent update at 1:40 am

The center said about 15 minutes later saw several “discrete supercells” that “matured in the open warm sector of the OK.”

“A tornado watch means conditions are favorable for tornadoes and severe thunderstorms in and near the watch area,” the center said. “People in these areas should be aware of threatening weather conditions and listen for further statements and warnings if any.”

Oklahoma’s governor reminded residents at a news conference Sunday night that Red Cross shelters are open for services and resources, while the state emergency center remains activated.

With more than 30,000 households experiencing power outages, Stitt said the state will prioritize opening polling places — with power available — by Election Day. If there are problems, he assured, voters will be notified and redirected as appropriate.

ABC News’ Kenton Gewecke and Vanessa Navarrete contributed to this report.