  The results of high-resolution spectral-line observations of dense molecular
gas are presented towards the nuclear region of the type 2 Seyfert galaxy
NGC1068. MERLIN observations of the 22 GHz H2O maser were made for imaging the
known off-nuclear maser emission at radio jet component located about 0.3"
north-east of the radio nucleus in the galaxy. High angular resolution ALMA
observations have spatially resolved the molecular gas emissions of HCN and
HCO$^{+}$ in this region. The off-nuclear maser spots are found to nearly
overlap with a ring-like molecular gas structure and are tracing an evolving
shock-like structure, which appears to be energized by interaction between the
radio jet and circumnuclear medium. A dynamic jet-ISM interaction is further
supported by a systematic shift of the centroid velocities of the off-nuclear
maser features over a period of 35 years. The integrated flux ratios of the
HCO$^{+}$ line emission features at component C suggest a kinetic temperature
T$_{k}$ $\gtrsim$ 300K and an H$_2$ density of $\gtrsim$ 10$^6$ cm$^{-3}$,
which are conditions where water masers may be formed. The diagnostics of the
masering action in this jet-ISM interaction region is exemplary for galaxies
hosting off-nuclear H2O maser emission.
