WASHINGTON (AFP) - A series of powerful tornadoes tore across the United States late Saturday, killing at least 21 people and shattering homes and businesses, officials and media said. Susie Stonner, spokeswoman for the Missouri department of emergency management, said there were 13 confirmed dead in her state as search-and-rescue workers on Sunday searched for survivors. Numerous tornadoes touched down in the evening hours as the storms ripped across Oklahoma at 55-70km per hour, killing seven in the area near Picher, Oklahoma, the state department of emergency management said. Some 150 people were injured. The high winds ripped roofs off houses, and other homes were crushed to kindling as the storms downed power lines, utility poles and trees. Oklahoma Governor Brad Henry declared a state of emergency in the disaster area, and planned to visit it later Sunday. "Our thoughts and prayers are with the people of Picher and all of the other Oklahoma communities that have been impacted by the latest wave of severe weather," Henry told CNN. National Guard troops were called to shut off access to Picher. The state said that about 6,300 homes and businesses were without electric power, including 3,000 near Tulsa. US President George W Bush called it "a sad day for those who lost their lives in Oklahoma and Missouri and Georgia because of the tornadoes." The storms barrelled eastward and killed one person in the Southeastern state of Georgia in the early morning hours of Sunday, that state's emergency management agency said. The small town of Kite, with some 1,000 residents, was apparently devastated. "From what I understand it has been completely destroyed," said department spokeswoman Lisa Janak. "It experienced significant damage." "Many roads are still blocked and impassable," she said. "They're having problems with trees in the road, so these are very preliminary estimates, but the town of Kite sustained significant, significant damage." Janak could not confirm whether the storm had spawned any tornadoes. "The National Weather Service will have to send out a survey team to determine that for sure," she said. Some 18,000 residents were without power in the state, Georgia Power told the Atlanta Journal Constitution. In February, a string of storms brought rare winter tornadoes to the Southern states of Tennessee, Arkansas, Kentucky and Alabama, killing 55 and injuring hundreds.