Lives may have been lost because of poor performance by the Welsh Ambulance Service, a report has found.
The report said improvements needed to be made
The Healthcare Inspectorate Wales (HIW) report followed claims by the service's ex-chief executive that failings meant 500 people were dying each year.
The inspectorate's report does not put a figure on how many people may have died, but said it was clear that improvements would save more lives.
The Welsh Ambulance Service said the report would help it to move forward.
The ambulance service has had a troubled year, beginning last May when acting chief executive Roger Thayne resigned after two months in the post, claiming the trust was in "crisis".
He wrote a report cataloguing outdated equipment, poor management and delays in ambulances reaching patients, which he said contributed to a "dangerous" service.
'Hope for future'
Mr Thayne also claimed 500 people were dying unnecessarily each year through the service's failings and under-funding.
His successor as interim chief executive, Anton van Dellen, also resigned after two months in the job, saying he was unable to commit long-term to the post.
Alan Murray said there was a will to improve the service
In August, Alan Murray was appointed chief executive and said improvements would be made by Christmas.
But in November, the latest official figures for ambulance performance showed emergency response times were the worst since 2003.
A Welsh assembly inquiry into the state of the service, headed by Auditor General Jeremy Colman, found a lack of direction and weak leadership led to longstanding poor performance by the service.
The report, released in December, made 28 recommendations for improvement.
The latest review, by independent body HIW, found that ambulance staff were "committed to providing good patient care" and that the arrival of the new chief executive had given them "real hope for the future of the service".
On the claim that of the 500 lives were being lost annually, the HIW reports said it was "very difficult to determine if this estimate is accurate" but said there was "clearly room for significant improvement".
'Will to improve'
Peter Higson, chief executive of HIW, said the trust faced "significant challenges".
He added: "There are reasons for genuine optimism that the trust's board and chief executive will meet these challenges and deliver the needed improvements through its modernisation plan."
The ambulance service's chief executive, Mr Murray said the report's 26 recommendations would help it in "understanding the challenges ahead as we move to implement our comprehensive modernisation plan".
On Mr Thayne's claim that 500 lives were being lost because of poor performance, Mr Murray said: "We never accepted that figure and neither did the auditor general in his report.
"There is obviously a correlation between the speed with which ambulances arrive and good patient outcomes.
"There have been problems in the past but there is a genuine will to improve the service."