A health board in Wales has been put in special measures following "serious and outstanding concerns".

Last month a damning report revealed patients suffered institutional abuse at a mental health ward at one of the hospitals run by Betsi Cadwaladr University Health Board, which covers the whole of North Wales and part of mid Wales.

Mark Drakeford, minister for health and social services, said a decision to put the health board in special measures was made at a meeting today.

"This significant decision is made in line with the escalation framework," he said.

"It reflects serious and outstanding concerns about the leadership, governance and progress in the health board over some time. A thorough and balanced assessment has taken place on areas of concern that will form the basis of actions to be taken as a result of special measures.

"Whilst the special measures apply to the health board, I want to reassure patients and communities served by the health board and staff working for it that day-to-day services and activities will continue as normal."

The board was put under targeted intervention in March 2014, the highest of any of the NHS organisations in Wales.

Following concerns, Mr Drakeford asked NHS Wales chief executive Dr Andrew Goodall to bring forward a meeting between the Welsh Government, the Wales Audit Office and Health Inspectorate Wales - as part of the NHS Wales escalation framework - to review and consider the health board's current status.

In a letter to Mr Drakeford, Dr Peter Higson, chairman of the health board, wrote: "I recognise the gravity of the situation and the need for swift remedial action.

"I will ensure that the Health Board and its officers will work and co-operate fully with the Welsh Government in achieving the necessary improvements for the benefit of the patients and public in North Wales."

Last month, the board's chief executive, Professor Trevor Purt, said he was "extremely sorry" for the treatment of some patients at the Tawel Fan ward of Glan Clwyd Hospital in Denbighshire, which he described as "shocking".

The independent investigation found there were regimes and routines on the ward which may have violated the human rights of patients and there was a "lack of professional, dignified, compassionate care".

The Welsh Conservatives said patients were "treated like animals" and doctors and nursing staff were "guilty of serious breaches of the professional standards".

North Wales Police decided in conjunction with the Crown Prosecution Service not to bring criminal charges in the case.