NEW : Death toll up to 24 Sunday and Monday , a witness says . NEW : The death toll is expected to rise as rescue workers continue their search for survivors in the rubble of collapsed buildings. U.N. official : Gadhafi 's regime gave `` no guarantees at all that the violence would cease '' Britain to help 5,000 escape Misrata .
NEW : Death toll up to 24 Sunday and Monday , a witness says . NEW : Misrata residents are `` let down by NATO , '' a witness says . U.N. official : Gadhafi 's regime gave `` no guarantees at all that the violence would cease '' Britain to help 5,000 escape Misrata .