  At ultra-relativistic energies the minijet production in heavy-ion collisions
becomes sensitive to semi-hard parton rescatterings in the initial stages of
the process. As a result global characteristics of the event, like the initial
minijet density, become rather insensitive on the infrared cutoff that
separates hard and soft interactions. This allows to define a nearly
parameter-free {\it saturation cutoff} at which the initial conditions may be
computed. As an application we study the centrality dependence of the charged
particle multiplicity, which is compared with present RHIC data and predicted
at higher energies.
