On 8 November 1960, an eleven-man patrol from Number 2 Platoon, A Company, 33 Infantry Battalion, ONUC, departed their base at Niemba, under the command of Lieutenant Kevin Gleeson.
Having dismounted at a crossing point on the Luweyeye River, twenty kilometres from Niemba, the patrol was attacked without warning by a large number of Baluba tribesmen.
Nine of the patrol died, eight at the ambush scene, and another was subsequently killed a few days later. The nine fatalities were the first operational casualties suffered by the Defence Forces since the Civil War in 1922 – 1923.
These nine deaths remain the highest toll from a single action, suffered by the Defence Forces in the cause of world peace. Twenty-six members of the Defence Forces died while serving with ONUC.
Trooper Anthony Browne who survived the initial attack, was posthumously awarded An Bonn Míleata Calmachta with Distinction. He was the first recipient of the Military Medal for Gallantry.
On 19 November 1960, those who died in the Niemba Ambush were accorded a State funeral and were buried with full military honours in the Army Plot in Glasnevin Cemetery.
Every year, since 1961, the Organisation of National Ex-Servicemen and Women (ONE) has hosted the Niemba Ambush commemoration ceremony in Cathal Brugha Barracks. Due to government restrictions arising from Covid-19, the 60th Anniversary commemoration hosted by the Minister for Defence was deferred to a later date. However, a restricted wreath laying ceremony took place in Cathal Brugha Barracks on Saturday, 7 November 2020.