Senior Government figures were briefed following the presence of drones in Irish skies on the night Ukrainian President Volodymyr Zelensky arrived in Ireland, RTÉ News understands.
Mr Zelensky landed at Dublin Airport for his first official visit to Ireland shortly before 11pm on Monday night.
It is understood that there is no garda investigation into the matter.
In a statement the Defence Forces said that for operational security reasons, it has "no comment on the specifics of any alleged incidents".
It said that Defence Forces' support to the security operation, led by An Garda Síochána, was "successfully deployed in multiple means" and that it lead to a "safe and successful visit" by Mr Zelensky to Ireland.
An Garda Síochána said "without commenting on any particular incident, any such incident occurring on Irish waters is a matter for the Defence Forces".
The Irish Aviation Authority (IAA) had implemented a no-fly zone for drones over and around Dublin to coincide with Mr Zelensky's visit.
