MEMPHIS, TN --Seven people were killed in Tennessee and four in northern Mississippi by a line of storms that brought heavy flooding and tornados to the region over the weekend. More rain and storms loomed Sunday as emergency officials in Tennessee sought help from the state's Army National Guard, and urged people to stay off roads and interstate highways turned into raging rivers. At a Sunday news conference, Tennessee Gov. Phil Bredesen said it will likely be days before floodwaters recede enough to thoroughly assess the damage to roads and bridges. Tennessee officials have confirmed 7 deaths. At least three people are missing after getting swept away by flood waters, and one of them is presumed dead by the Tennessee Emergency Management Agency, which would bring the death toll to 8. Bredesen said he expects to ask for federal disaster designation. Earlier Sunday, TEMA asked for the state's National Guard to help with rescue operations. Agency spokesman Jeremy Heidt confirmed that one person died around 4 a.m. Sunday in a tornado near Pocahontas, about 70 miles east of Memphis. The other deaths in Tennessee were all due to flooding, TEMA said. Interstate-24 remained closed in Nashville, and segments of I-40 between Nashville and Memphis were blocked. "The big message we're trying to get out is stay off the road," TEMA spokesman Mike Browning said. "It's really dangerous for a lot of people to be out there right now." In northern Mississippi, Benton County Coroner John Riles said two people were killed in a mobile home that "looks like you stuck about four sticks of dynamite on it and it just disappeared." Riles said a two-story house nearby also was obliterated. "If you didn't know the house was there, you'd think it was a vacant lot," he said. In Lafayette County, Emergency Management coordinator David Shaw said one person was killed in Abbeville, where 15 or 20 houses were damaged by strong winds. A spokeswoman at the National Weather Service said it was too early to say if tornadoes had caused the damage in Mississippi. A line of strong thunderstorms Saturday dumped at least 10 inches of rain on Memphis and produced tornadoes and hail along the Mississippi River Valley in Mississippi, Arkansas, Missouri, Kentucky and northward. The forecast called for more rain through the day Sunday, which could stymie rescuers trying to reach all of the far-flung areas that have been affected. Some areas were hit by 13 inches of flash flooding on Saturday, and the same was expected on Sunday, Browning said. "This thing is not going to be over this weekend by any means," he said. The weekend deaths came on the heels of a tornado in Arkansas that killed a woman and injured about two dozen people Friday. The southwestern part of Tennessee was extremely hard hit, with several Memphis-area streets declared impassable. Corey Chaskelson, a meteorologist with the National Weather Service, said a levee had been breached along the Big Creek River in Millington, to the north of Memphis. He said 4 to 5 feet of water had flooded 200-300 homes at the Naval Support Activity base in Millington. Emergency officials in Shelby County said hundreds of people were being evacuated due to high water, including residents of the Navy base and inmates at a federal prison. Bob Nations, director of the Shelby County Office of Preparedness, said most of the roads into and out of Millington had been cut off by flooding. At the Baker Community Center in Millington, where a Red Cross shelter was set up, retiree Joe Curry, 74, said he and his wife were rescued from their home in a boat Saturday morning after the water had risen to 7 feet. "It rose so fast we couldn't get out," said Curry, who spent the day at the Red Cross shelter until family members could pick him up. "It's a mess." Erick Hooper, 19, said there was water in his living room when he woke up Saturday morning. "It kept rising, and it was too cold to swim, so I went on the roof," he said. Hooper spent the day on the roof of the mobile home until rescuers picked him up in a boat. A pillow and a blanket were all he managed to take with him. Jerry Fritts of the Red Cross said about 100 people were expected to spend the night at the Millington shelter. Waters were washing away parts of roads and bridges in the Jackson area, said Marty Clements, director of the Jackson-Madison County Emergency Management Agency. "We've basically become an island because the major highways and roads are cut off," he said Saturday evening. Clements said there have been gas leaks and water main breaks due to the flooding and both area hospitals were running on generators temporarily during the day. He said emergency officials have asked all events be canceled on Sunday, even church services, to keep people from trying to venture out in the floodwaters. Charles Shannon, a spokesman for the Nashville Fire Department, said one person drowned in flood waters on Interstate 24 south of Nashville. In Nashville, emergency responders had rescued 50 people from flooding, Mayor Karl Dean said. Police Chief Ronal Serpas said two police officers had to be rescued from a tree. The National Weather Service said up to 12 inches of rain had fallen along areas of Interstate 40 since midnight and up to 6 more inches was expected through Sunday. In Arkansas, Gov. Mike Beebe declared a state of emergency after visiting a community south of Little Rock hit hard by Friday's storms, and he was scheduled Sunday to visit heavily damaged areas north of the city.