  We prove optimal dispersive estimates for the wave group
$e^{it\sqrt{-\Delta+V}}$ for a class of real-valued potentials $V\in
C^{(n-3)/2}({\bf R}^n)$, $4\le n\le 7$, such that $\partial_x^\alpha
V(x)=O(|x|^{-\delta})$ for $|x|>1$, where $\delta>(n+1)/2$.
