The Taoiseach has appealed to Irish people to observe one minute's silence at 3.10 p.m. today. Mr Ahern will attend the Act of Prayerful Reflection at the Court House Building in Omagh at 2.45 p.m.
Commemorations of the bombing will be held throughout Ireland today. They include:
Omagh: The Act of Prayerful Reflection in Omagh town centre (2.45 p.m.) will include a minute's silence.
Belfast: A special service in St Anne's Cathedral begins at 3 p.m. The cathedral will be open tomorrow from 9 a.m. until 4 p.m. for private prayers.
Acts of Prayerful Reflection will also take place elsewhere in Belfast today at 3 p.m. Venues include the Good Shepherd Church, Ormeau Road; Cregagh Presbyterian Church, Cregagh Road; The Park, Kingsway, Dunmurry; The Park (opposite the Ulster Hospital), Dundonald; Shankill Road Memorial Garden; Belfast Central Mission, Glengall Street; St Peter's Cathedral, St Peter's Square, Falls Road; and Cavehill Shops, off the Cavehill Road.
Co Derry: Guildhall Square, Derry (2.45 p.m.); The Diamond, Coleraine (3 p.m.); The Diamond, Magherafelt (2.45 p.m.); War Memorial, Limavady (3 p.m.).
Co Fermanagh: The Diamond, Enniskillen (3 p.m.)
Co Armagh: Market Street, Armagh (3 p.m.); Town Centre, Portadown (3 p.m.).
Co Down (3 p.m. unless otherwise indicated): War Memorial, Ballynahinch; Marcus Square, Newry; Newry Street, Banbridge; Lower Square, Kilkeel; War Memorial, Hillsborough; Queen's Hall, Newtownards; The Maypole, Holywood; Bloomfield Methodist Church, Banbridge; The Cenotaph, Comber; Newcastle; Down Cathedral, Downpatrick; McKee Clock, Bangor (2.45 p.m.).
Co Antrim (3 p.m. unless otherwise indicated): All Saints, Antrim; Community Centre, Whitehead, Carrickfergus; Market Square, Lisburn; The Square, Ballyclare; War Memorial, Carrickfergus; Inver Memorial Gardens, Larne (2.45 p.m.); First Broughshane Presbyterian Church, Broughshane, Ballymena (2.30 p.m.); Ballymoney Town Hall (2.55 p.m.); Loanends Presbyterian Church, Templepatrick (2.50 p.m.)
Co Tyrone (3 p.m. unless otherwise indicated): The Cenotaph, Cookstown; St Macartan's Cathedral, Clogher; Killyman Church, Dungannon; The Square, Dungannon (2.45 p.m.); The Diamond, Castlederg (2.45 p.m.).
Monaghan: A short act of worship will be held in front of the Court House in Monaghan town at 3 p.m.
Cork: An inter-church prayer service will take place on the steps of Cork City Hall at 3 p.m. and will be relayed by public address to the surrounding streets.
Dublin: Archbishop Desmond Connell has asked that the bells of Catholic churches throughout the Dublin diocese should toll at 3.10 p.m. He will celebrate a special Mass in the Pro-Cathedral at 12.45 p.m.
A prayer service will be held in St Canice's Church, Finglas, from 2.45 p.m. to 3.15 p.m. today. The Christian churches in Lucan will conduct a prayer service for the people of Omagh on Lucan Village Green at 2.45 p.m.
Four commemoration services will be held in Christ Church Cathedral, Dublin, today. At noon there will be two minutes of prayers for peace; a 25-minute requiem for Omagh begins at 12.45 p.m.; there will be a 20-minute memorial service at 3 p.m.; followed by choral evensong at 5 p.m.
A Time of Prayer, in memory of the victims of the Omagh bombing, will be held outside St Ann's Church in Dawson Street, beginning at 3 p.m.
Dun Laoghaire: A vigil will take place at 3 p.m. in York Road Presbyterian Church, Dun Laoghaire. An ecumenical service begins in St Paul's Church, Adelaide Road, Glenageary, at 2.45 p.m.
Co Kildare: An inter-denominational service will be held in St Brigid's Cathedral, Kildare, at 3 p.m.
Co Wicklow: An open-air ecumenical prayer service will be held at the Glencree Centre for Reconciliation at 2.45 p.m.
London: Two memorial services will be held in London this weekend: a memorial Mass at the Irish Centre in Camden Town and a service in the Church of St Martin-in-the-Fields in central London.
The one minute's silence will be observed by all businesses, at all bus and rail stations in the North and at all soccer matches there. The Irish Football Association has put back the kick-off time of all games to 3.15 p.m.
Tomorrow
The President, Mrs McAleese, will attend a memorial service at 3.15 p.m. in St Patrick's Cathedral, Dublin. The Lord Mayor of Dublin, Senator Joe Doyle, will attend. The Gospel will be read by the President and the lessons by the Spanish ambassador, Mr Jose Maria Sanzpastor, and by Mr Alan Rainey, vice-chairman of Omagh District Council. The chairman of the council, Mr Sean Clarke, and the chief executive, Mr John McKinney, will attend the ceremony.
Prayers at the service will be led by Ms Michelle O'Brien, whose mother was killed in the Dublin bombing of 1974, when Michelle was eight years old.