  We consider the diffusion-controlled annihilation dynamics $A+B\to 0$ with
equal species diffusivities in the system where an island of particles $A$ is
surrounded by the uniform sea of particles $B$. We show that once the initial
number of particles in the island is large enough, then at any system's
dimensionality $d$ the death of the majority of particles occurs in the {\it
universal scaling regime} within which $\approx 4/5$ of the particles die at
the island expansion stage and the remaining $\approx 1/5$ at the stage of its
subsequent contraction. In the quasistatic approximation the scaling of the
reaction zone has been obtained for the cases of mean-field ($d \geq d_{c}$)
and fluctuation ($d < d_{c}$) dynamics of the front.
