SCUFFLES broke out between protesters and gardaí as a list of those who died in the Easter Rising, including British soldiers, was unveiled at Glasnevin cemetery in Dublin.
Around 100 protesters gathered outside the cemetery on Sunday morning. Attempts were made to set fire to a Union flag but it was too wet to catch light.
A firework and several smoke bombs were thrown on the ground towards gardaí during minor disturbances.
A 15-year-old boy was arrested outside the cemetery on suspicion of throwing the firework. He was taken to Mountjoy Garda Station.
During the interfaith ceremony at Glasnevin, the names of 488 people known to have died in the Rising - including 268 civilians - were unveiled on granite stones.
There has been some controversy about the inclusion of the names of 119 British soldiers, some of whom are buried in Glasnevin, on the "Necrology Wall".
Sinn Féin TD TD Aengus Ó Snodaigh criticised the inclusion of the soldiers' names.
He said his party "believe it is totally inappropriate for a memorial wall to list indiscriminately together Irish freedom fighters and members of the British crown forces".
The Glasnevin Trust has insisted the memorial is an attempt to present the historical facts, without hierarchy or judgment.
John Green, chairman of Glasnevin Trust, told the service the wall reflected modern Ireland.
"Behind each and everyone of these lost lives is a story of heartbreak, no matter what side the person served on or indeed for those innocently caught up in the conflict," he said.
"One hundred years on we believe this memorial reflects the time we live in, with the overwhelming majority of the Irish people wishing to live in peace and in reconciliation.
"But it is for each visitor to take from the wall what they wish."
Senior clerics from several faiths and humanist representatives were among those to speak at the ceremony.
The project drew inspiration from an international memorial near Arras in France that lists the names of 580,000 people killed in fighting on the western front in the First World War.
Caretaker Taoiseach Enda Kenny attended yesterday morning's service.
Mr Kenny laid a wreath after several local school children were invited to unveil the new memorial wall. A minute's silence was observed before the last post was sounded and the Tricolour raised from half to full mast.
The service concluded with the playing of Amhran na bhFiann.
