  We present the results of a cluster search in the Fermi-LAT Pass 8 gamma-ray
sky by means of the Minimum Spanning Tree algorithm, at energies higher than 10
GeV and at Galactic latitudes higher than 25 degrees. The selected clusters
have a minimum number of photons higher than or equal to 5, a high degree of
concentration, and are without a clear corresponding counterpart in blazar
catalogues. A sample of 30 possible gamma-ray sources was obtained. These
objects were verified by applying the standard Maximum Likelihood analysis on
the Fermi-LAT data. A search for possible radio counterparts in a circle having
a radius of 6 arcmin was performed, finding several interesting objects, the
majority of them without optical spectroscopical data. These can be considered
as new blazar candidates. Some of them were already noticed as possible blazars
or Active Galactic Nuclei in previous surveys, but never associated with high
energy emission. These possible counterparts are reported and their properties
are discussed.
