Gardai have carried out a search in Roscommon in connection with an investigation into international invoice fraud.
Four men have also been arrested as part of inquiries following searches in various parts of the country.
A number of planned searches were carried out in Roscommon, Cork and Tipperary this morning and the men, aged between 23-35 were subsequently detained for questioning.
They are currently being held at Middleton, Fermoy, Mallow and Tipperary Garda stations under Section 50 of Criminal Justice Act.
Three of the arrests this morning were made under Operation BOXPLOT, which targets a Criminal Organisation based in the North Cork area, that is believed to be laundering the proceeds of international invoice re-direct (BEC) fraud through bank accounts in Ireland.
The fourth man was arrested under Operation SKEIN, which targets a Criminal Organisation based in Ireland involved in similar international, criminal activity.
To date, 17 people have now been arrested as part of Operation SKEIN and 4 persons arrested under Operation BOXPLOT. Investigations are ongoing.