Obama says he wants everyone affected to know that the federal government is on the ground to help. He says the Federal Emergency Management Agency will work with local officials.
Obama says, quote, "Your country will be there to help you recover and rebuild, as long as it takes."
The president is also praising the heroic efforts of first responders and neighbors.
A broad tornado killed at least 11 when it sliced through suburbs in Arkansas on Sunday at the start of the U.S. tornado season. Another person died in Oklahoma.
Obama spoke at a joint news conference with Philippine President Benigno Aquino while traveling in Asia.