South Vietnamese soldiers under the Roman Catholic President Ngo Dinh Diem <a href="https://en.wikipedia.org/wiki/Huế_Phật_Đản_shootings" id="mw-g" rel="mw:WikiLink" title="Huế Phật Đản shootings">open fire on Buddhists</a> defying a ban on the flying of the Buddhist flag on <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Vesākha" id="mw-w" rel="mw:WikiLink" title="Vesākha">Vesak</a>, killing nine and sparking the <a href="https://en.wikipedia.org/wiki/Buddhist_crisis" id="mw_A" rel="mw:WikiLink" title="Buddhist crisis">Buddhist crisis</a>.