  We present a mechanism based on internal self-annihilation of dark matter
accreted from the galactic halo in the inner regions of neutron stars that may
trigger the full or partial conversion into a quark star. We explain how this
effect may induce a gamma ray burst that could be classified as short,
according to the usual definition based on time duration of the prompt
gamma-ray emission. This mechanism differs in many aspects from the most
discussed scenario associating short gamma-ray bursts with compact object
binary mergers. We list possible observational signatures that should help to
distinguish between these two possible classes of progenitors.
