  We report the results of our exploratory program carried out with the
Southern Astrophysical Research (SOAR) telescope aimed at associating
counterparts and establishing the nature of the Fermi Unidentified gamma-ray
Sources (UGS). We selected the optical counterparts of 6 UGSs from the Fermi
catalog on the basis of our recently discovered tight connection between
infrared and gamma-ray emission found for the gamma-ray blazars detected by the
Wide-Field Infrared Survey Explorer (WISE) in its the all-sky survey. We
perform for the first time a spectroscopic study of the low-energy counterparts
of Fermi UGS, in the optical band, confirming the blazar-like nature for the
whole sample. We also present new spectroscopic observations of 6 Active
Galaxies of Uncertain type associated with Fermi sources (AGUs) that appear to
be BL Lac objects. Finally, we report the spectra collected for 6 known
gamma-ray blazars belonging to the Roma BZCAT that were obtained to establish
their nature or better estimate their redshifts. Two interesting cases of high
redshift and extremely luminous BL Lac objects (z>1.18 and z>1.02, based on the
detection of Mg II intervening systems) are also discussed.
