The blast on the afternoon of 7 October in the village of Creeslough, in northwestern Ireland, caused the death of four men, three women and three children, with ages ranging from five to 59.

Police said two men, both in their 50s, were arrested on Friday morning for alleged offences contrary to the Non-Fatal Offences Against the Person Act 1997.

A Gardai spokesperson said today: "The two males arrested yesterday have been released without charge.

"The investigation led by Gardai in Donegal division is ongoing with the intention of submitting a file to the Office of the Director of Public Prosecutions."

The fatal explosion at the building complex came as a shock to the village of 400, where almost every family would have known someone who was either killed or injured in the tragedy.

Robert Garwe and his five-year-old daughter Shauna Flanagan-Garwe, Catherine O'Donnell and her 13-year-old son James Monaghan, fashion student Jessica Gallagher, Celtic fan Martin McGill, Sydney native James O'Flaherty, shop worker Martina Martin, carpenter Hugh 'Hughie' Kelly and 14-year-old Leona Harper were killed.

Local Gardai in Donegal have been leading the investigation, supported by the Garda National Bureau of Criminal Investigation (GNBCI) and other agencies, including the Health & Safety Authority (HSA) and the Commission for the Regulation of Utilities (CRU).