Authorities said at least two tornadoes touched down in southern Mississippi late Wednesday and early Thursday, damaging dozens of homes and businesses and injuring residents in a small town.

No fatalities were immediately reported, but authorities and rescue crews were still responding to the damaged areas north of Magee, said Stephanie Bryant, a dispatch supervisor with the Simpson County Sheriff's Department.

"We have widespread damage throughout the state but our hardest-hit community is in Simpson [County]," said Katherine Gunby, spokeswoman for the Mississippi Emergency Management Agency.

The exact number of injuries isn't yet known, but two people had been flown by helicopter to the University of Mississippi Medical Center in Jackson. Their conditions were not yet available.

At least 60 homes have suffered varying degrees of damage, Gunby said.

"Tornadoes are such powerful, fast storms and when they hit at this time of year at night when people are sleeping, people might not have been able to get to interior rooms, safe places or shelters fast enough," she said. "So we are going to be watching out for that and I suspect we will be taking more people to hospitals today."

Magee Mayor Jimmy Clyde told NBC's Today show that the town about 64 kilometres southeast of Jackson was in "dire straits."

"We have no power," he said. "Most of the roads into and out of our city are blocked. It damaged our water supply. We don't know the extent of the damage as of yet."

There were other reports of downed trees, power lines and damaged homes across the Deep South from a band of severe weather that spawned heavy thunderstorms and high winds.

Another reported tornado touched down in Mississippi's Lauderdale County on Wednesday night, heavily damaging nine homes and a business, but no injuries were reported, MEMA officials said.