The death toll of a tornado touched down earlier Saturday in southern U.S. state of Mississippi has climbed to seven, officials said.

The tornado razed across mid-eastern Mississippi, leaving a trail of destruction and dead bodies in its wake. Three people were killed in Choctaw County, another three perished in Yazoo County and one died in Holmes County, according to Jeff Rent, an official with Mississippi Emergency Management Agency.

Two of the victims were believed to be minors and the toll could rise as rescuers cleared debris left behind by the deadly tornado.

"We are still trying to account for all the residents impacted by the storm," said Rent.

Yazoo City Mayor McArthur Straughter described the tornado, reported to be over a kilometer wide, as "devastating," and dozens of buildings sustained extensive damage or totally leveled.

The tornado razed through areas including Valley Park, Yazoo City and Durant. It then moved northeast toward Alabama.

Mississippi Governor Haley Barbour declared state of emergency in 17 counties, and called in the National Guard. He said in a statement that the tornado and storms "have left many Mississippians with destroyed businesses and without homes."

Authorities in Mississippi said they were conducting emergency response in affected counties. Barbour said he is pleased with the emergency response, praising citizens of their "character and perseverance."

Heavy storms swept across southeast United States on Saturday. The sky was darkened as rain and lightning were seen across the region. Many areas were put under tornado watch.