Update as of 4: 21 a.m. EDT: Two people were reportedly killed in Tennessee Tuesday, taking the latest toll from a massive storm system that has triggered powerful tornadoes across the southern and central U.S. to 11, including at least nine people who were earlier reported killed in Mississippi and Alabama. Further threats to life and property in the region from tornadoes could continue for several more days, reports said. On Monday, the death toll inflicted by the tornadoes in the states of Arkansas, Oklahoma and Iowa had climbed to 18.

At least nine people were killed Monday in Mississippi and Alabama after a massive storm system triggered powerful tornadoes that tore through the central and southern parts of the U.S. for a second day in a row.

As many as six were reported killed in Alabama, although only two deaths had been confirmed so far. The National Weather Service reportedly issued warnings for more tornadoes in Alabama while at least seven were reported killed in Mississippi by 12 tornadoes that hit the state. Tornadoes spawned Sunday by the severe weather had claimed at least 18 lives so far, with Arkansas accounting for 16 deaths while one death each was reported in Oklahoma and Iowa.

"It was real bad. We're trying to pull people out," Bart Aguirre, Tupelo Police Chief told Reuters, referring to emergency crews that were going house to house and searching damaged buildings in the community of about 35,000 in northeastern Mississippi.

Tupelo Mayor Jason Shelton told Reuters: “I am just encouraging everyone to stay inside and be weather aware. There is still a very real danger of another line coming through and people still need to be inside.”

George Grabryan, director of emergency management for Florence and Lauderdale counties, in northwest Alabama, told Fox News that about 16 shelters were opened before the storms hit the state.

"There's a lot of sensitivity up here," Grabryan said. "I've got a stack of messages here from people, many of them new to the area, wanting to know where the closest shelters are."

Mississippi Gov. Phil Bryant reportedly said the hardest-hit areas were Tupelo and Winston counties near the town of Louisville. Parts of western Georgia and Tennessee also were at high risk as the storm system headed east toward the Mid-Atlantic states.