At least 21 people have been arrested in Dublin as part of an investigation into the activities of criminal gangs and dissident republican groups.
A major garda operation took place today and more than 50 searches were carried out.
Four men and a woman were arrested under European arrest warrants.
They were brought to the Bridewell Garda Station pending extradition proceedings before the High Court.
Another 16 people are being held at garda stations around Dublin.
The operation involved local and specialist units, including the Garda National Drugs Unit and the Organised Crime Unit.
Gardaí said that Operation Wireless was set up under the direction of Garda Commissioner Martin Callinan with a number of selected targets.
Mr Callinan said there will be further such operations as gardaí investigate the death of dissident republican Alan Ryan.
