  The source IGR J17200-3116 was discovered in the hard X-ray band by INTEGRAL.
A periodic X-ray modulation at ~326 s was detected in its Swift light curves by
our group (and subsequently confirmed by a Swift campaign). In this paper, we
report on the analysis of all the Swift observations, which were collected
between 2005 and 2011, and of a ~20 ks XMM-Newton pointing that was carried out
in 2013 September. During the years covered by the Swift and XMM-Newton
observations, the 1-10 keV fluxes range from ~1.5 to 4E-11 erg/cm^2/s. IGR
J17200-3116 displays spectral variability as a function of the pulse phase and
its light curves show at least one short (a few hundreds of seconds) dip,
during which the flux dropped at 20-30% of the average level. Overall, the
timing and spectral characteristics of IGR J17200-3116 point to an accreting
neutron star in a high-mass system but, while the pulse-phase spectral
variability can be accounted for by assuming a variable local absorbing column
density, the origin of the dip is unclear. We discuss different possible
explanations for this feature, favouring a transition to an ineffective
accretion regime, instead of an enhanced absorption along the line of sight.
