Fluctuations of Strangeness and Deconfinement Phase Transition in Nucleus-Nucleus Collisions

We suggest that the fluctuations of strange hadron multiplicity could be sensitive to the equation of state of strongly interacting matter created at the early stage of high energy nucleus--nucleus collisions. They may serve as an important tool in the study of the deconfinement phase transition. We predict, within the statistical model of the early stage, that the ratio of properly filtered strange to non-strange hadron multiplicities should have a non--monotonic energy dependence with a minimum in the mixed phase region.