The leader of Pembrokeshire council has admitted children have been harmed by a small number of employees.
In a letter to the Welsh Government, the council says it is liaising with the police on about 25 cases which it dealt with using internal procedures.
BBC Welsh affairs editor Vaughan Roderick says the admission appears to contradict the council's earlier claim.
It had said criticisms of its child protection measures were about the "potential harm rather than harm".
The council's letter explains that in saying no children were harmed it was referring to the consequences of the weaknesses of its disciplinary procedures, and not the cases that led to them.
BBC Wales understands that many of the cases involve the physical abuse of children in education.
John Davies, who is also leader of the Welsh Local Government Association, is embroiled in a row with Education Minister Leighton Andrews over child protection.
Mr Davies has been criticised over his response to two critical inspection reports.
The dispute flared after education services for children and young people were judged "unsatisfactory" by schools inspectorate Estyn, which said the "policies and systems for safeguarding children and young people are not fit for purpose".
A report exposing the council's failings over child abuse allegations was then described as "deeply disturbing" by Wales' children's commissioner.
Mr Davies said at the time that he wanted to assure parents staff were working tirelessly to ensure children were as safe as possible.
But the Welsh Government then accused Mr Davies on Wednesday of trying to play down the reports' seriousness in some media interviews.
That criticism was contained in a letter from Mr Andrews and Social Services Minister Gwenda Thomas.
'Lack of rigour'
"Your authority has demonstrated a lack of rigour and urgency in undertaking this work, as evidenced by the fact that it was not until the inspectors started to point out some of the issues that your authority even realised that there was a problem," wrote the ministers.
"Even then, in one case inspectors had to refer back to your officers four times before all the action that was needed was taken."
Mr Davies responded earlier this week by saying some comments in the letter were factually inaccurate.
In his letter to the ministers, released on Friday, he said: "I and all my colleagues are extremely sorry that in a number of cases, children were harmed by a small number of employees of the authority.
"Investigation of their wrongdoing resulted in disciplinary action including termination of contracts.
"The analysis by Care and Social Services Inspectorate Wales concluded that the application of systems and procedures relating to some of those investigations was insufficiently rigorous and consistent, thereby potentially creating a risk of further harm to children.
"We view that conclusion with the utmost seriousness and we are all determined to improve safeguarding arrangements as our top priority."
He later added: "In conclusion, I respectfully ask you to measure us on what we have done to date in immediate response to the concerns you have raised."
A Welsh Government spokesperson said: "We stand by our letter.
"There is a process now in place. The ministerial advisory board will report by the 16 September. Ministers will then decide on what actions to take."