NEW : At least 12 have been killed , including a 3-month - old , state police spokesman says . All share harrowing stories of encounter with twister . Five of the dead were in Choctaw County , in north central Mississippi . President Obama has ` ` been briefed on the situation in Mississippi , '' he says .
NEW : At least 10 have been killed , including a 3-month-old , state emergency official says . Survivors share harrowing accounts of encounter with twister . Five of the dead were in Choctaw County , in north central Mississippi . President Obama has `` been briefed on the tragedy in Mississippi , '' spokesman says .