  Exact solutions with an exponential behaviour of the scale factors are
considered in a multidimensional cosmological model describing the dynamics of
n+1 Ricci-flat factor spaces M_i in the presence of a one-component perfect
fluid. The pressures in all spaces are proportional to the density: p_i = w_i
\rho, i = 0,...,n. Solutions with accelerated expansion of our 3-space M_0 and
a small enough variation of the gravitational constant G are found. These
solutions exist for two branches of the parameter w_0. The first branch
describes superstiff matter with w_0 > 1, the second one may contain phantom
matter with w_0 < - 1.
