(CNN) -- At least two people were killed when two houses sitting next to one another exploded in Indianapolis early Sunday, a fire department spokeswoman said.
The cause of the blast was not immediately known, Indianapolis Fire Department spokeswoman Bonnie Hensley said.
About 200 residents in the neighborhood were evacuated to an elementary school, authorities said. More than a dozen will spend the night in a shelter, they said.
"The debris field is blocks; there's insulation and construction materials scattered," Hensley said.