Gardaí have arrested four men in a major crackdown on Republican dissidents ahead of the visit of Prince Charles next week.

It is understood a leading figure in the Republican movement was arrested, as officers carried out more than 20 searches in Louth, Wexford and Dublin.

The four men are being held over alleged offences including directing terrorism, membership of an unlawful organisation, and possession of explosives.

Bomb disposal experts spent several hours decommissioning devices in a number of locations yesterday.

Conor Feehan of The Herald newspaper told Newstalk Breakfast gardaí may have prevented a serious attack during the visit of Prince Charles.

While the Justice Minister Frances Fitzgerald says she is satisfied with the security operation in place ahead of the visit.