Gardai recovered two guns and made a number of arrests after a car failed to stop at a Covid-19 checkpoint in the early hours of yesterday.
Two men and a woman were taken into custody, while a large quantity of suspected drugs was recovered during the incident in Dublin.
Members of the Dublin Metropolitan Region (DMR) Roads Policing Unit, based at Dublin Castle, were conducting a Covid-19 checkpoint along the quays at around 4.30am when a car approached.
The vehicle was signalled to pull over but failed to do so and sped away.
A short time later the vehicle crashed along Ellis Quay and a bag was seen to be thrown by an occupant car into the Liffey. The three people in the vehicle, two males and a female, were later arrested.
Divers from the sub-aqua unit were called to the scene carry out a search for the bag, and when it was recovered, two suspected handguns and a large quantity of drugs were retrieved.
The weapons were sent for ballistics examination and the drugs for analysis.
The three suspects are currently being held at separate garda stations in the south inner city.
Meanwhile, gardai arrested seven people for breaching Covid-19 health guidelines after being given additional powers last week.
There were also a further 144 incidents in which people breached guidelines. These were dealt with through other legislation.
Most of these involved gardai being called to house or street parties in which gatherings were taking place beyond the family unit or where people were undertaking non-essential travel.
However, Garda Commissioner Drew Harris said the vast majority complied with the restrictions.
Gardai had been able to arrest a person on suspicion of being in breach of the virus guidelines, but officers took a "last resort" approach to enforcement.
"There was a very high level of compliance with the public health guidelines over the Easter weekend. This has helped saved lives," Mr Harris said.
"Regrettably, there was a small minority who did not adhere to the guidelines or other legislation and garda members had no option but to use the regulations or other legislation."
Over the bank holiday weekend, gardai conducted 150 permanent checkpoints as part of Operation Fanacht, while 500 shorter and mobile checkpoints were also in operation.