At least four people were killed and dozens of homes were destroyed by a tornado that ripped through the Hattiesburg area in southern Mississippi, officials said.
Mayor Johnny DuPree signed an emergency declaration for the city.
Hattiesburg police and firefighters are going door-to-door to try to rescue victims, officials said via the city's Twitter account.
Check out some photos of the damage caused by the storm that ripped through the southeastern part of the state.
The National Weather Service warned the storm could produce "quarter size hail."
Greg Flynn of the Mississippi Emergency Management Agency said "massive damage" was reported across a three country area that was struck by the tornado around 4 a.m.
Downed power lines and debris covered large areas of the town. Residents are being urged to stay indoors and avoid traveling.
The state's Highway Patrol is also reporting Interstate 59 is closed due to debris.
More severe weather is expected to move through the area until around 8 or 9 a.m.
Flynn said the tornado hit three counties. It touched down in Lamar, plowed through Forrest and then struck Perry before dissipating.
And the storms aren't over yet. More severe weather is expected to move through the area until around 8 or 9 a.m.
The Associated Press contributed to this report.