The Moderator of the Presbyterian Church in Ireland is to step down after an internal report uncovered serious safeguarding issues in the church.
Dr Trevor Gribben made the announcement at a news conference in Belfast this afternoon.
He said people had been put at risk and some had been harmed.
While he has only been the moderator for some months, he has previously held the most senior positions in the church for many years.
For years he was effectively the church's chief executive.
'Serious and significant failings'
He said an internal investigation and report had found "serious and significant failings" between 2009 and 2022.
"As a result of this people have been placed at risk.
"We are aware of a number of people who have been harmed and we believe there may well be others as yet unknown to us.
"We apologise unreservedly for this," he said.
He did not take questions at the news conference, leaving it to colleagues to field media queries.
It is the first time a moderator has stepped down in the church's history. It was founded in 1840.
Rev Gribben said although he was not directly responsible for the delivery of safeguarding in the church, serious failings had occurred on his watch as General Secretary.
"I have made these decisions and taken these steps with the deepest personal regret that our central failings have caused such harm to those who deserve our protection the most."
The Presbyterian Church in Ireland has around 180,000 members belonging to more than 500 congregations.
Its membership is predominately in Northern Ireland but there are significant congregations in Dublin and the border counties of Monaghan, Cavan and Donegal.
Dr Gribben will be replaced by another senior church figure Rev Dr David Bruce at the end of this month.
Setting out further details on the failings that were uncovered, Rev Dr Bruce said there had been times when the church had failed to make referrals to statutory agencies when these were required.
At times the church had not responded adequately when concerns were raised.
In some instances offenders returning to worship in church following referrals by statutory agencies had been inadequately monitored.
He said none of this should have happened.
"We have let you down and for this I am truly sorry."
He said he was not able to detail the scale of the abuse because the number of victims was still unknown. So far the numbers of people known to have been directly affected was "in the low single figures" reporters were told.
All the statutory authorities, including the police were now involved. Reporters were told the church was "reluctant to define harm" in order not to exclude potential victims.
People who had been affected are being encouraged to come forward with their stories.
