Two men have been arrested in connection with the murder of a prison officer in Northern Ireland.

The men, aged 31 and 44, are being questioned about the shooting of David Black on the M1 motorway on Thursday morning.

Father-of-two Mr Black, 52, was gunned down as he drove to work at the high security Maghaberry prison in Co Antrim.

Police have blamed dissident republicans for the attack.

The men were arrested in the Lurgan area in Co Armagh.

Dissidents have been engaged in a long-running campaign against conditions in Maghaberry.

Mr Black was shot on a stretch of the motorway between Portadown and Lurgan.

A Toyota Camry used in the attack was later found burned out in the Inglewood area of Lurgan.

Mr Black, from Cookstown, Co Tyrone, had served in the Prison Service for more than 30 years and was considering retirement.