Ireland's president and political leaders have cast their votes in a referendum to decide whether to liberalise its strict abortion laws.
Polls for the historic vote opened across the country at 7am, with citizens opting to either retain or repeal the Eighth Amendment of the state's constitution, which prohibits terminations unless a mother's life is in danger.
Counting will begin on Saturday morning, with the result expected later that day.
Amid reports of a brisk morning turnout, President Michael D Higgins and his wife Sabina cast their votes in Dublin at 9.30am while Taoiseach Leo Varadkar, a vocal advocate for repeal, voted in the city around 11.15am.
"I always get a little buzz from voting, it just feels like it is democracy in action," Mr Varadkar said after emerging from the polling station at Castleknock.
"Not taking anything for granted of course, but quietly confident - there's been good turn out across the county so far and hoping for a yes vote tomorrow.
"Obviously, I would be encouraging everyone to come out and vote, a high turn-out would be to the advantage of the yes campaign."
He urged voters not to be distracted by the sunny weather and exercise their democratic right.
Leader of the main opposition party, Fianna Fail's Micheal Martin, voted to repeal in his constituency in Cork while Sinn Fein President Mary Lou McDonald also cast a Yes vote in Dublin.
However, her Sinn Fein party colleague and vocal anti-abortion campaigner Peadar Toibin called on Irish people to vote No to "abortion on demand".
"The irony that the referendum on abortion is being held on International Missing Children's Day will not be lost on many Irish people," he Tweeted.
"Those on the margins of society suffer most from abortion. Vote No to Abortion on Demand."
A total of 3.3 million citizens are registered to vote, with 6,500 polling stations open across the country.
The referendum is asking whether people want to repeal the Eighth Amendment and replace it with wording that would hand politicians the responsibility to set future laws on abortion, unhindered by constitutional strictures.
The Catholic Church is among influential voices arguing that the life of the unborn should be sacrosanct, but the retain campaign faces a major challenge from a Yes camp which has portrayed itself as modernising and in step with international opinion.
If the public votes Yes, the Irish Government intends to legislate by the end of the year to make it relatively easy for a woman to obtain the procedure in early pregnancy.
Ministers have promised to allow terminations within the first 12 weeks, subject to medical advice and a cooling-off period, and between 12 and 24 weeks in exceptional circumstances.
The debate during eight weeks of campaigning has been divisive, with the leaders of all the main political parties, including Fine Gael leader Mr Varadkar, backing change.
They argued that a Yes vote represented the compassionate choice for thousands of Irish women forced to travel to England for the procedure.
Opposing them was a vocal No camp, including the bishops, which insisted the life of the child is sacrosanct and interference in that right is immoral.
Campaigners against change have used emotive language to highlight the threat to the foetus and warned against "extreme" proposals from the Government which could be expanded in future years.
Opinion polls have been tight, with most showing the Yes side in the lead.
The indication is that rural voters are more likely to say No than their urban counterparts, while a significant number of "don't knows" have cast a degree of uncertainty over the outcome.
Around 2,000 voters in 12 islands off the mainland were eligible to vote on Thursday to prevent any delay in counting their ballot papers.
The Eighth Amendment is a clause in the constitution which was written after a previous referendum on the issue in 1983 recognised the right to life of the unborn child.
It protects the equal right to life of the mother and the unborn and effectively prohibits abortion in most cases.
In 1992, women were officially given the right to travel abroad, mostly to the UK, to obtain terminations. Pro-repeal campaigners said almost 170,000 have done so.
The liberalisation campaign gathered momentum after an Indian dentist, Savita Halappanavar, died in hospital in Galway aged 31 when she was refused an abortion during a miscarriage.
Her husband, Praveen Halappanavar, said she repeatedly asked for a termination but was refused because there was a foetal heartbeat.
In 2013, legislation was amended to allow terminations under certain tightly restricted circumstances - the Protection of Life During Pregnancy Act.
When doctors felt a woman's life was at risk due to complications from the pregnancy, or from suicide, they were permitted to carry out an abortion.
Under pressure from the UN about alleged degrading treatment of women who travelled to England for terminations, the Irish Government began exploring the possibility of further reform, culminating in the calling of this referendum and the promise to legislate.