  The presence of an obscuring torus around the nucleus of Seyfert galaxies, as
supposed in the popular unification scheme, can strongly modify the X--ray
spectrum for both type 1 and 2 Seyfert galaxies. We find that if the torus is
Compton thick, it can scatter at small angles a significant fraction of the
nuclear radiation, and contribute to the continuum of Seyfert 1 galaxies above
$\sim$10 keV, and to the fluorescence iron line at 6.4 keV. At large
inclination angles and for large torus column densities, the spectrum is
attenuated by photoabsorption and Compton scattering, while the iron
fluorescence line produced by the torus can have large equivalent widths. Even
after dilution by the continuum scattered by the warm material outside the
torus, this iron line could be strong enough to explain the ``cold" component
in the spectrum of NGC 1068. We stress that the complex pattern of the
predicted variability can be a powerful tool for constraining the parameters of
the model, such as the column density of the torus, its inclination and the
amount of warm scattering material.
