  Context. Several bright emission line regions have been observed in the
central 100 parsecs of the active galaxy NGC 1068. Aims. We aim to determine
the properties and ionization mechanism of three regions of NGC 1068: the
nucleus (B) and two clouds located at 0.3" and 0.7" north of it (C and D).
Methods. We combined SPHERE (0.95 - 1.65 um) and SINFONI (1.5 - 2.45 um)
spectra for the three regions B, C, and D. We compared these spectra to several
CLOUDY photoionization models and to the MAPPINGS III Library of Fast Radiative
Shock Models. Results. The emission line spectra of the three regions are
almost identical to each other and contribute to most of the emission line flux
in the nuclear region. The emitting media contain multiple phases, the most
luminous of which have temperatures ranging from 104.8 K to 106 K. Central
photoionization models can reproduce some features of the spectra, but the fast
radiative shock model provides the best fit to the data. Conclusions. The
similarity between the three regions indicates that they belong to the same
class of objects. Based on our comparisons, we conclude that they are shock
regions located where the jet of the active galactic nucleus impacts massive
molecular clouds.
