  We report on observations aimed at searching for flux variations from the
proposed IR counterpart of the Anomalous X-ray Pulsar XTE J1810-197. These
data, obtained in March 2004 with the adaptive optics camera NAOS-CONICA at the
ESO VLT, show that the candidate proposed by Israel et al. (2004) was fainter
by Delta H=0.7+/-0.2 and Delta Ks=0.5+/-0.1 with respect to October 2003,
confirming it as the IR counterpart of XTE J1810-197. We also report on an
XMM-Newton observation carried out the day before the VLT observations. The
0.5-10 keV absorbed flux of the source was 2.2x10^-11 erg/s/cm^2, which is less
by a factor of about two compared to the previous XMM-Newton observation on
September 2003. Therefore, we conclude that a similar flux decrease took place
in the X-ray and IR bands. We briefly discuss these results in the framework of
the proposed mechanism(s) responsible for the IR variable emission of Anomalous
X-ray Pulsars.
