  In Xu and Kuang (\textit{J. Phys. A: Math. Gen.} 39 (2006) L191), the authors
claim that, for single-mode excited entangled coherent states $|
\Psi_{\pm}(\alpha,m)>$, \textquotedblleft the photon excitations lead to the
decrease of the concurrence in the strong field regime of $| \alpha | ^{2}$ and
the concurrence tends to zero when $| \alpha | ^{2}\to \infty$". This is wrong.
