LITTLE ROCK - Tornadoes ripped through the south-central United States on Sunday, killing at least 12 people in Arkansas and Oklahoma and wiping out entire neighborhoods of homes, according to officials, as rescue workers searched in darkness for survivors.An aide to Arkansas Governor Mike Beebe said five people had died in both Faulker and Pulaski counties, with another fatality reported in White County.Two people were killed in Vilonia, a small town in Faulkner county in central Arkansas of some 3,800 people, and rescuers were digging through the rubble of ruined buildings looking for more victims, according to authorities there.A spokesman for the Faulkner County Sheriff's office had said there was a "mass casualty situation", and numerous injuries were reported. TV footage showed houses ripped off their foundations, with cars toppled on top of the rubble."Tonight, I walked around what was only hours earlier a thriving neighborhood that is now gone. An entire neighborhood of 50 or so homes has been destroyed - many homes are completely gone except the foundation," U.S. Representative Tim Griffin told Reuters."And there is more devastation like this in other parts of Arkansas," Griffin said.One person died when a tornado tore through Mayflower, 22 miles (35 km) northwest of Little Rock, at about 7:30 p.m., officials there said.In Mayflower, some of about 45 homes were destroyed in a newer subdivision and a lumberyard was damaged, said Will Elder, an alderman in the city of 2,300 people. He said at least one person was injured.The tornado passed through the east side of town, tearing up trees and bringing down powerlines, making it difficult for the emergency services to find stricken areas in the darkness, and forcing authorities to shut down Interstate 40."It's extremely hazardous here right now," said Elder. "The power lines are down, roads are blocked and they will have to proceed with caution." At least one person was killed in a tornado in a small Oklahoma town in the northeast corner of the state, according to Ottawa County Sheriff's Department spokesman Derek Derwin.Media and the National Weather Service reported that two people were killed.That twister was spotted in Quapaw, 200 miles (322 km) northeast of Oklahoma City at about 5:45 p.m., according to the weather service. An Ottawa County, Oklahoma, police dispatcher said a search and rescue effort was underway in Quapaw, but could not confirm reports of fatalities.