item spacing inside the alertblock is tighter than item spacing inside block

[darteaga]

See the following:

\begin{block}{Normal block}
    \begin{itemize}
        \item This
        \item spacing
        \item is
        \item more relaxed
    \end{itemize}
\end{block}

\begin{alertblock}{Alert block}
    \begin{itemize}
        \item This
        \item spacing
        \item is
        \item tighter
    \end{itemize}
\end{alertblock}

Actually the same can be seen in the default example provided.

I prefer the more relaxed spacing. How can I make them equal?