The tornado that ripped through the Forrest County seat of Hattiesburg, Mississippi, was believed to have reached three-quarters of a mile in diameter at times, Reuters reported quoting Anna Weber, a National Weather Service meteorologist.
The weather service counted three separate twisters in south-central Mississippi Sunday evening.
On the Hattiesburg campus of the University of Southern Mississippi, the storm damaged several buildings, including a performing arts center and an alumni house, but no one was hurt, the university said in a statement.
Some 10 or 15 people were injured by the tornado that slammed Hattiesburg and other parts of the county, but none of the injuries was serious, news agency reports citing officials said.
The storm that hit the city of Hattiesburg proceeded into downtown Petal causing destruction to more than 100 houses along with several businesses.
In neighboring southwestern Alabama, authorities reported a flurry of seven tornadoes across three counties, including one that damaged 46 homes in Clark County, Weather Service meteorologist Keith Williams told Reuters.