The Garda ombudsman has launched an investigation after a loaded gun fell from the boot of a police car.
The Garda Siochana Ombudsman Commission (GSOC) will investigate the incident after the gun went missing for a time in Dublin on Tuesday.
A passerby found the sub-machine gun with ammunition and handed it into the city’s Store Street Garda Station.
There have been reports that the GSOC became aware of the incident through a story in the media.
A Garda spokesman said that an internal investigation into the incident has been launched.
He said: “A senior Garda officer has been appointed to examine all the circumstances surrounding an incident involving an armed Garda unit in Dublin city centre.
“Inquiries are ongoing.”
The spokesman added that the unit concerned is involved in the Dublin region targeting organised criminal activity and was not part of the security detail attached to the royal visit.