'Within seconds, everything changed'

NEW: Damage is reported at a university and a high school Tornado warnings remain in effect for parts Mississippi and Alabama At least three people are injured in Marion County "Within seconds, everything changed," says a resident of Hattiesburg, Mississippi

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(CNN) -- A tornado touched down in southern Mississippi on Sunday, injuring at least three people and causing widespread damage, state officials said.

As the storm system moved east, tornado warnings remained in effect for parts of southeastern Mississippi and southwestern Alabama.

"Right now, the most important thing for us is to make sure that we account for all individuals and make sure that they're safe and secure," Robert Latham, director of the Mississippi Emergency Management Agency, told CNN.

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He said there were reports of significant damage in Hattiesburg, where the tornado touched down. The city is home to the University of Southern Mississippi.

"I hope to goodness that when all this is said and done, all we have to do is clean up a mess and that we haven't lost any lives in this," Latham said.

The university suffered damage to several buildings, but there were no reports of injuries there. University police declared a state of emergency and urged those not on campus to stay away until further notice.

Nearby Oak Grove High School similarly suffered damage. Randy Wright posted photographs to his Twitter account of the school, showing debris strewn on what looked to be a parking lot, and a truck upside down in a baseball diamond.

He said there were tons of downed power lines and trees.

Sara Lawrence, a resident of Hattiesburg, said that the storm sounded like "stuff being thrown."

"Within seconds, everything changed," she told CNN. "I didn't feel like there was much notice. I heard the sirens and everything looked OK outside, so I started making preparations to go into the bathroom. And then, next thing I know, all the lights went out, and it got dark outside."

Brett Carr with the Mississippi Emergency Management Agency reported that the three injures occurred in Marion County. It was not immediately clear how they were hurt.

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