Two suspected dissident republicans have been arrested over the murder of prison officer David Black.
The men aged 51 and 34 were detained in the Irish Republic over the killing of Mr Black in a drive by gun attack on the M1 motorway last year.
The prison officer, a father of two, was shot dead as he drove along from his home in Cookstown, Co Tyrone to Maghaberry prison just outside Lisburn, Co Antrim.
Gardai in the Republic said they arrested two men as part of investigations into dissident republican activities and the murder.
A number of searches were carried out in the Leitrim and Cavan areas.
The two men were detained under Ireland's anti-terror laws, section 30 of the Offences against the State Act, and were being held in the Cavan area. They can be detained for up to 72 hours.