  IGR J18483-0311 is a poorly known transient hard X-ray source discovered by
INTEGRAL during observations of the Galactic Center region performed between
23--28 April 2003. Aims: To detect new outbursts from IGR J18483-0311 using
INTEGRAL and archival Swift XRT observations and finally to characterize the
nature of this source using the optical/near-infrared (NIR) information
available through catalogue searches. Results: We report on 5 newly discovered
outbursts from IGR J18483-0311 detected by INTEGRAL.For two of them it was
possible to constrain a duration of the order of a few days. The strongest
outburst reached a peak flux of 120 mCrab (20--100 keV): its broad band
JEM--X/ISGRI spectrum (3--50 keV) is best fitted by an absorbed cutoff power
law with photon index=1.4+/-0.3, cutoff energy of ~22 keV and Nh ~9x10^22
cm^-2. Timing analysis of INTEGRAL data allowed us to identify periodicities of
18.52 days and 21.0526 seconds which are likely the orbital period of the
system and the spin period of the X-ray pulsar respectively. Swift XRT
observations of IGR J18483$-$0311 provided a very accurate source position
which strongly indicates a highly reddened star in the USNO--B1.0 and 2MASS
catalogues as its possible optical/NIR counterpart. Conclusions: The X-ray
spectral shape, the periods of 18.52 days and 21.0526 seconds, the high
intrinsic absorption, the location in the direction of the Scutum spiral arm
and the highly reddened optical object as possible counterpart, all favour the
hypothesis that IGR J18483-0311 is a HMXB with a neutron star as compact
companion. The system is most likely a Be X-ray binary, but a Supergiant Fast
X-ray Transient nature can not be entirely excluded.
